For it to be an ad hominem it would have to be something irrelevant...

Excusing Biden for pulling a standard trump method, is a relevant comparison to what trump supports excuse from trump.

Words have meaning.

https://en.m.wikipedia.org/wiki/Ad_hominem

If I pointed it out that it's also disappointing trump and Biden supporters both don't seem to understand that definitions matter, it wouldnt be an an ad hominim either. Because it's now relevant to the topic at hand.

If you're upset at the comparison, maybe Biden supporters should stop acting like trump supporters?