Yes, that's been my experience so far as a nominator although as a writer a lot of my writing about Palestine has been boosted (so not impossible!). I hesitate to speculate about things I cannot know for certain but yes there is evidence that specifically use of the word "genocide" with relation to Palestine is grounds for rejection. See the comments here from a Medium staff member: https://sallyprag.medium.com/whats-with-boosting-non-factual-politicised-divisive-opinions-but-not-boosting-the-jewish-voice-57143f2ac515