In response to the removal: it's not transphobic, when I end the message with "wait, that last part is actually true" ("so they're actually transphobes"), it makes a very clear implication that everything that came before it was just sarcastic mockery and not actually true. Hope I could clear that up.
Something like a "quote" might be helpful in establishing that you're echoing their sentiment to mock them rather than making it seem like you're just going "No U" with their transphobic arguments.