I agree the former poster made a claim of evidence that should be backed up, but you did the same as well. Thus you’re both just as responsible to cite a source when asked.

It's not about who is responsible. If I had evidence to back my claim up, regardless of who made the initial assertion, I'm going to.

My guess is that neither can find anything with a quick google search and are just hoping that this thread dies.

Incorrect. If I thought earlier posters were intent on engaging sincerely I would continue, but evidence here and previously suggests they are employing derailing tactics masquerading as reasonable argument.

You're incorrect. Regardless of their reason, it does not derail an argument for you to provide sources. It bolsters your case.

Refusing to provide citations makes it seem like you have something to hide, regardless of the others' intention.