When someone picks a hero you think is bad in that game, that meta, that role, whatever reason it is bad for, if it's already picked, don't say anything. All you are going to do is tilt them, and yourself, and make both of you play worse. Don't make a hard game harder.
Most teams are not some God draft, and that includes the enemy team. Should you go out of your way to pick bad picks? No, I'm not saying that at all. But at the end of the day, you have heroes to click stuff and cast spells, so just play the game. What's done is done. And besides, wouldn't you rather someone pick a niche hero they are good at than a meta one they are garbage at? I know I would.
My example is my last game. I played BB carry, Jugg was mid, OD was offlane, and my supports were Zeus and Enigma. Enigma and OD were both mad at everyone's picks, the rest of us didn't care. OD picked specifically to spite us, but Enigma picked first phase, knew Enigma 5 is a trend, but didn't know Zeus 4 and BB carry are also a trend. His hero name describes him well honestly.
OD just ditched offlane for really no reason, and went to farm, and I also had to disable help because he was griefing me with 'Astral Imprisonment'. Enigma left my lane to go jungle after I died and he just stood there and watched me with 'Malefice' off cooldown. I would go on to die just one more time for the duration of the match, and I stomped them as soon as I bought my Aghanim's. Their draft was supposedly better (it wasn't), they were winning heavily early, and we won anyway.
Moral of the story, just play the video game.
Source: https://www.reddit.com/r/DotA2/comments/vqe186/your_mentality_to_an_already_picked_hero_can_be/