When you work to help Apple lock down their operating system, you are helping an oligopoly (Apple along with Google and Microsoft) to control the future of all software development. The mitigations that are put into the operating system serve two purposes: sure, they lock out invaders... but they also lock out the user and rightful owner of the hardware.
The moral costs of the latter do not pay for the benefits of the former. I look at people who work for Apple on security as similar to people who work for the TSA: yes, they are probably in some way contributing to the safety of people... but they are actively eroding the liberties of people in such a frightful way that the benefits are not worth the cost.
So when I see people working for either the TSA or for Apple, I ask myself "did they really really need this job? or could they have gotten work elsewhere"; and if the answer is that they didn't absolutely need to work for Apple, I model them as someone who has left the Resistance to go work for the Empire because they thought laser guns were cool and the Empire happened to have a larger laser gun for them to work on, and hell: the Empire is managing to maintain order on a large number of planets, right? :/
In case you think that this is just some future concern, it is a war which is already playing out today in countries like China, where the government knows that Apple has centralized control of what can be distributed on that platform and uses that knowledge to lean on Apple with threats of firewalls and import bans to get software and books they dislike redacted.
https://www.nytimes.com/2017/01/04/business/media/new-york-t...
> Apple, complying with what it said was a request from Chinese authorities, removed news apps created by The New York Times from its app store in China late last month.
> The move limits access to one of the few remaining channels for readers in mainland China to read The Times without resorting to special software. The government began blocking The Times’s websites in 2012, after a series of articles on the wealth amassed by the family of Wen Jiabao, who was then prime minister, but it had struggled in recent months to prevent readers from using the Chinese-language app.
Having a centralized point of control at Apple is not helping the lives of these Chinese citizens, at least according to the morals that I have (and I would have guessed you have, but maybe you are more apologetic to these regimes than I; we have never really spent that much time talking as opposed to just kind of "sitting next to each other" ;P).
So, yes: I absolutely am against security experts "helping Apple secure iOS" when what we know is actually happening is that they are "helping Apple enforce censorship by regimes such as the Chinese government on their citizens". There are tons of places in the world you can go work for where your work on security will actually be used for good: go work for one of those companies, not the oligopoly.