I'm not sure the things listed are the same as 'painting pictures'. I'm not even saying you're wrong about Cromwell, but at least take the points fairly.
* The third was something that happened in Cromwell's reign, but there's no evidence he contributed positively or negatively, and the fact that the monarchy followed up by supporting it and actually chartering the royal society seems to indicate that it had little connection to what the actual regime in power was.
* Primary education good, sure.
* So I was not familiar with the anglo-dutch war so I read the wikipedia article. This appears to be a trade dispute because the English wanted to look the dutch out of shipping to England that was escalated to war by the English after the Dutch refused their ultimatum? This is being offered as a "good" act?
So overall, I don't think funding primary education is an achievement that even begins to counterbalance his actions, sorry.
Besides, to go back to the example of Hitler (and no, this is not Godwin's law, Hitler is the most appropriate comparison to Cromwell in Irish history), Hitler was _great_ for technology. The germans started modern rocketry which led to our modern satelite communications, the allies invented computing, both sides made big leaps in industrial production.
I don't think anyone sensible thinks the above should be considered in a judgement on Hitler's actions. Neither do I think education/scientific funding should excuse Cromwell's.
About his patronage for science: he was more interested in training up preachers, but he wouldn't have seen these as opposed. He planned to set up colleges in the North; Hartlib (key figure in the Invisible College) was on the committee for Durham. These plans were ended by the Restoration.
You're very casual about primary education! It wasn't seen as an obviously good thing at the time - which is why it was reversed. Even in the 19th century, many people still argued that you shouldn't over-educate the working masses. Early literacy may have been a crucial step towards the take-off into economic growth.
There's a lot of people making the comparison with Hitler. I suggest that even the harshest interpretation of the Irish campaign does not bear comparison with the industrialized murder of the Holocaust. English colonization predates Cromwell by at least a century. Ethnic cleansing was planned and carried out in several areas of Ireland. This is, obviously, very bad indeed! But it is not the same as Zyklon gas. The plan had also been laid down before Cromwell became Protector. When he intervened personally, it was usually to urge mercy for specific individuals. This is not the same as "no Hitler, no Holocaust".
Lastly, you're assuming that I only wanted to mention "good stuff". I just wanted a slightly broader and calmer debate. I don't know the historical effects of defeating Spain or Holland.
In comparison, Hitler in Poland is 16%. [1]
Another factor that makes it an appropriate comparison: Like Hitler dispossessed Poles to give their land to Germans, Cromwell dispossessed Irish Catholics to give their land to English and Scottish Protestants.
[1]: Materski, Wojciech; Szarota, Tomasz (2009). "Przedmowa" [Preface]. Polska 1939–1945. Straty Osobowe i Ofiary Represji pod Dwiema Okupacjami [Human Losses and Victims of Repressions under Two Occupations] (in Polish). Warsaw: IPN. ISBN 978-83-7629-067-6. Archived from the original on 23 March 2012. Retrieved 27 October 2014.
Percentages are important, but Hitler was responsible for the death of millions. Absolute numbers matter too.
I looked more into the history. (Your cite doesn't give 600,000 for the figure killed by Cromwell, but for the whole civil war. In fact, the author ends "One wonders how many of the c. 600,000 victims died during Cromwell's campaign." The cite there is to Michael St John Parker, which I can't find.) I'm still hunting for reliable estimates of the population decline. Houston and Houston "Population history" isn't available online. The writers in Ohlmeyer (cited below) don't seem to put up a headline figure. William Petty's estimates aren't modern enough to be useful, although Petty was a serious writer. Note two points. First, population decline isn't the same as causing deaths, especially in a young population. Iraq after 1990 saw "missing population" of up to a million due to sanctions, but this is probably not because a million people were directly killed. You also have to account for declining birth rates and emigration. For instance, marriages fell sharply at the start of the civil war period. Other deaths were due to famine and starvation. Again, these are appalling, buut they are not the same as murder in death camps.
More importantly, these are figures for the entire 1641-1661 conflict. But Cromwell was only there relatively briefly. He didn't start the conflict, nor finish it. He became a shorthand for the whole English policy of the period. That is not necessarily fair to him.
None of this makes Cromwell innocent. (Still less does it make the English leadership as a whole innocent.) But the Hitler comparison are still overblown:
* Cromwell took part in a brutal colonial civil war, which devastated the Irish economy and led to famine and disease. He was responsible for massacres at Wexford and Drogheda.
* Hitler committed deliberate, systematic genocide against at least two ethnic groups, setting up scientific-industrial systems of mass murder which killed millions.
These are not the same.
Things I read while learning more about this:
https://academic.oup.com/past/article-abstract/195/1/55/1523...
Rai, M., 1993. Columbus in Ireland. Race & Class, 34(4), pp.25-34.
Ohlmeyer, J.H. ed., 2002. Ireland from independence to occupation, 1641-1660. Cambridge University Press.
Update. The most serious, detailed estimates I could find are:
Lenihan, P., 1997. War and population, 1649–52. Irish Economic and Social History, 24(1), pp.1-21, available at
https://search.proquest.com/docview/1292941669/fulltextPDF/A...
These give an estimate of population decline of 15-20%, mostly due to famine and plague (which the war was instrumental in spreading).
https://physicstoday.scitation.org/do/10.1063/PT.6.4.2018092...