Why are conservatives defending Derek Chauvin ?

I haven't heard very many who are. I'm guessing your sources of information parade out any they can find to give the narrative you and they simply WANT to have about Conservatives on this matter. This is nothing but intellectual dishonesty on your part!

This being said, there is wide difference of opinions on how much Chauvin contributed to Floyd's death ranging from 1st degree murder to some sort of manslaughter.

Because he did nothing wrong except arrest a criminal.

The simple answer is racism.  The responses you'll get though will relate to George Floyd's criminal history, drug use, etc.  None of those excuse Chauvin sitting on his neck until he dies of course, but that's what they are rolling with.

The video from the event is absolutely horrific.  Pondering your question, the only reason I can see for defending Chauvin is racism.  Sad but true.

@Michael. I didn't take either political side. I took the side of humanity. 

Because everything must be politicized and Blue Team had already taken the side of Floyd.