Does my sentence have parallelism?
"He criticizes public schools because they are compulsory, government-funded, and destroying students' humanity."
The only parallel construction here is in the three attributes the speaker assigns to schools: "compulsory, government-funded, and destroying students' humanity." each of these links with "are", so the construction is parallel to that degree. But the attributes are expressed with different forms. The word "compulsory" is a simple adjective. the term "government-funded": is compound, and uses an -ed form that suggests a past action, although not in this case, but that reduces the parallelism. And "destroying students' humanity."uses a gerund form "destroying" which is at least awkward and arguably incorrect here.
He criticizes public schools because they are compulsory, government-funded, and they destroy students' humanity.
would be better, in my view, but still not very parallel.
No, the last coordination
compulsory, government-funded, and destroying students' humanity
connects two adjectives and a clause.
This would be parallel:
compulsory, government-funded, and humanity-destroying.
That would be three adjectives, though the last adjective doesn't convey the same meaning as "destroying children's humanity".
It would be better to rephrase the original sentence:
"He criticizes public schools because they are compulsory and government-funded, and are destroying students' humanity."
He criticizes public schools because they are compulsory, government-funded, and destroying students' humanity.
No, this sentence currently doesn't show parallelism. You can rephrase it as follows:
He criticizes public schools because they are compulsory, government-funded, and humanity-destroying.
Now all three terms are adjectives which is how you would form parallelism in this case. Either all adjectives or all nouns or all prepositional phrases, etc.