Of course you don't HAVE TO, but it does help when one is attempting to persuade others.
And that is Debate 101.
No, I'm not. These are well-established rules of logic. Attacking the source does not refute the information.
No- there is nothing I MUST do. I made the point I wanted to make.
The only point you made is that the ADL is a left-wing organization whose information should be taken with a grain of salt. You have not shown that this actual information is incorrect. If the ADL is wrong on this issue, you should easily be able to refute them.
The fact that you keep avoiding the question of whether this evidence is wrong leads me to conclude that you have no information that can refute it.