What is the ruling on Making Tabdee’?

Also, my advice due to a previous question: Youngsters should avoid talking ill about the people of Ilm (Islamic knowledge). Also, they shouldn’t search (for mistakes), this one made a mistake and this one didn’t make a mistake. However, when he makes a mistake, if one is able to inform and advise him, then he should do it. And even when a person makes a mistake, making tabdee’ of him (calling him an innovator) shouldn’t be pursued, because he is a sinful unjust innovator. Allah might guide him. Undoubtedly, a Muslim must be keen on pushing away what would divide the Ummah (nation) and give rise to grudges and hatred in it.