No, it's not normal for the streamers to win so often on slots while streaming. But, to be honest, I don't care.
Do I trust the casinos, that have such sneaky marketing practices? I really can't say that I have total trust in any online casino whatsoever, but this doesn't stop me from gambling on those casinos. I just don't bet absurd amounts of money and I try to gamble as moderately as possible.
I would never waste my time watching a streamer play slots games. What's interesting in watching streamers play slots games? This is totally boring BS, if you ask me. If you want to play slots games, you could play them for free. Just download a slots game app on Google Play and play the slots game for free. What's the point of watching a streamer play a boring game(that is probably rigged) and achieve fake and unrealistic results?