Based on your comments, I would say he's ruffling some feathers (as you said). He is saying things that are very likely to get a negative, and potentially dangerous, response. Troubled waters (problematic waters) is a common phrase in English (bridge over troubled water, for example), but the rest is not exactly an idiom, more poetic language. He is potential causing problems in an already volatile situation; playing with fire. He's put himself in a situation that is already slightly volatile and is stirring things up. Splashing around is quite playful phrasing, so it could imply that he doesn't realise what sort of danger, or difficulty, he is potentially putting himself in.

I mean it makes it easier for people to help you if you can give a bit more context to the question. That way you are likely to get more responses. I'll add an answer for you.

I can certainly assume what this speaker is trying to say, but I wondered why he had used this idiomatic expression.

You can search the surrounding text by holding down Ctrl + F on the page. The story is about this Korean American who has become "woke" due to the BLM movement after living in a conservative white culture in the U.S. He gave an unplanned speech at a rally in Korean Town, L.A, He used the age-old stereotypes of Asian Americans as complacent, quiet and not politically engaging. His stereotyping ruffled the feathers of the speakers on this show.

I had a quick look, but this is a long transcript and I didn't want to trawl through the whole thing looking for the section. You might want to summarise it a little and/or add more of the surrounding text. I can tell you what the phrase means ("playing with fire" or "putting himself in a difficult situation), but it is a little contextual. Without more context it's hard to tell you exactly what he's talking about and give you a full answer.