These kind of laws are called „Schutzgesetze“. Protection laws. Where individual rights are limited to protect individuals from what lawmakers perceive as negative effects.
You are definitely free to your opinion on this. It’s a social difference. I wouldn’t want to have it differently. Otherwise employers tend to force employees to work more than that time „by choice“. (Read: force by peer pressure etc)
The problem with the second part is that contracts have hours you need to work noted in them. If you have one contract for 40 hours and another for 8 per week, without telling either employer about this, you’re likely not committing fraud. Just fireable offices due to the contract disputes you mentioned.
But if you have two 40 hour contracts, either you will have to work 80 hours a week (the lesser offense, and in reality „wo kein Kläger da kein Richter“. German Idiom for „where there’s nobody to sue, there is no justice (to rule on this)“ ) or commit fraud by not working the 40 hours for at least one employer. (I’m talking about Arbeitszeitbetrug here) (Betrug = fraud)
The issue is, generally people in these kind of stories always work less than they should. I’d be majorly annoyed if a colleague fucked me over because he was working a second job at the same time.
Personally, my code of ethics is pretty simple. Be fair. That means I expect my employer to be fair to me, and I will be fair to my employer. So this whole overemployment thing rubs me the wrong way, just as an employer forcing people to do overtime would.
To be 100% clear. I have nothing against sidegigs. Those are also semi-common in Germany. But you should be open with your employer about it and not fuck over your colleagues by scheduling work for both at the same time.
As for your link. They’re talking about the employer side and how to deal with sidegigs. All relevant from what I saw. They didn’t touch on what to do if an employer is lying about his hours worked, unless I missed it.
They are very much correct with the part about being a freelancer being a possible „workaround“. Freelancers aren’t bound to the work time issues, as they aren’t employees. Being a freelancer is more complicated than in the USA though, from what I understand.
As a general point, in Germany working multiple jobs is less common than in the USA, at least from what I can gather from US social media. So that might explain one of the disconnects we are having here.