My DS4 is a really lovely, intelligent boy but has his moments of hitting out like all 4 year olds.
He attends nursery, and has hit out a few times saying his friends have annoyed him. Teachers have been dealing with this putting him on time out, and I have been doing behaviour Reward charts at home with him to stop him hitting/pushing.
Teacher pulled me aside today and told me a few different parents have complained about DS, and not wanting their kids to play with him. (Although we’ve also had problems of said parents children hitting my DS leaving marks etc but I’ve never complained as I know they’re still learning at that age.) 
I’m trying my best to stop this behaviour but this has made me feel awful like I’m not doing enough. AIBU to feel like this? Or are the other parents being unreasonable the kids who attend are 2-4 years old so surely it comes with the territory?