Well, engineers can have a lot of ethical responsibility. A resume that show you have no scruples doing unethical things is a fine way to gauge if someone is a suitable match.
Not much different then background checks for working in schools or what ever.
If a founder or person in charge of hiring views a candidate as a threat to either the business or their customers then they have every right to pass on that candidate.
>This is akin to persecuting people for their politics.
Whether or not this is a bad thing strictly depends on the politics.
Accountability == Witch Hunt? Where have I heard this before...
Which is something people do. For example, you wouldn't hire someone who takes their politics to just-under-violent extremist levels, as it would be bad PR.