Bears QB Justin Fields has been the victim of so many cheap shots since he joined the league. Indeed, we saw on many occasions last year where he had already given himself up and still receive a pretty significant blow. This is very dangerous for quarterbacks. The idea of a slide is to protect the player and I could make a strong case that it is almost more dangerous when the quarterback still receives a hit while/after sliding.
Here is another example. Thankfully Fields was ok. I would also like to add that I absolutely loved the reaction from his teammates that immediately went to his defense. They need to show that this is innaceptable.