Rotten Tomatoes is just a tool, and one I've generally been fine with and find useful on occasion. Sure there are outliers, but I can't say I've seen many (if any) sub 50% movies that I didn't think were awful. Sometimes you can find an entertainingly awful film, but glancing at a rotten tomatoes score, even if it doesn't dissuade me, has never really done me any wrong, and has certainly kept me from watching some garbage (or at least waiting until certain movies are on TV/a streaming service I have/available at the public library for free to watch some stuff).
I honestly find people that complain about it to be a bit ridiculous. Its a website that takes reviews and puts them together to say if they're more positive or negative, there is nothing inherently wrong with that and if you don't like it you can ignore it. That said the fan percentage is usually worthless because of review bombing.