What is an alternative to "Perpetrator" with a more neutral connotation?

Solution 1:

From a comment under the question, I see that adherents is what was being looked for. However, I think that followers is more natural in this context:

[Merriam-Webster, from the verb follow]
2 a : to engage in as a calling or way of life : PURSUE
       // wheat-growing is generally followed here
2 b : to walk or proceed along
       // follow a path
3 a : to be or act in accordance with
       // follow directions
3 b : to accept as authority : OBEY
       // followed his conscience

Using it in the example sentence:

He criticized the revolution and its followers.

The criticism of a revolution is often of the principles involved and the followers of those principles. These things can exist before, during, and after the revolutionary event itself.

Google Books Ngram Viewer indicates that and its followers is more common than and its adherents: