I get that it goes against the fundamentals of crypto currency, but exactly for what reasons though? Assuming you're not using it for anything illegal (if you are then it's understandable), why the concern? I'm asking specifically when trading.
It simply goes against the privacy of an individual whether a trader or not. The online trading is suppose to protect your identity against theft because you don't know the next person, hackers are everywhere also. The reason also is that decentralised and digital economy doesn't really require the data disclosure of the next person, you need to be careful with who you are dealing with because it is not a safe environment.