That's a long way of saying you can't back up your claim
You say that all or most politically motivated mass shooters are liberal. Prove it. You're making the claim so show the data.
And saying that any liberal source is lying without even looking at the facts is a sign of major dishonesty
I have looked into it and I have done the research and that's why I can back up what I say. But you can't which is why you're backing down and trying to shift the burden of proof. If you make a claim, it's not on someone else to prove you wrong.
If you want people to take you seriously you better be prepared to back up what you say with evidence
Neo Nazis and white supremacists are pretty much always conservative. They are on the fringe right, but they are conservative and they stand for conservative values.
You don't get to just remove a bunch of people to skew the data in your favor. That's not how it works.
That's like taking a test and getting half the answers wrong and saying "if you ignore the answers I got wrong, I did very well!"