It is normals, that does not mean they were boosted
Just got out of a normals game and my team was ridiculing the enemy jungler, who was diamond 4, for being boosted.
Guys its normals, higher elo's don't play their mains in normals usually. It is okay if they do bad, it doesn't mean they were boosted. The champions they play might be completely different from the play style they are used to. For this reason challengers and master players will try new champions out in ranked, because of how stupid lower elo people act when a high elo doesn't do well. (well and other reasons but this is still a reason)
We call people out for shaming bronze and silver for being stuck there for 700+ games in a season and we say they are trying their hardest,yet this community feels no shame for degrading higher elo players for doing bad in a game, especially if its not a champion they play regularly. Sadly it is a pretty ingrained part of this community that I don't think will ever be fixed...