If you notice it was a qualified statement, meaning there was another part after "homer" modifying what homer means in this instance. I think you are a true Jimmer homer if you think he is closer to parker than to Reddick. This means that you are blinded by your LOVE of his game enough to compare him to a far superior player rather than a player that he is more likely to emulate. After further discussion with Archie on the subject I can see that was not his argument, but it appeared that way to begin with.
I am sure Jimmer might be a NBA caliber talent. He obviously has skills that would probably translate well. But if you convince yourself he is the next Parker in the making you are being unrealistic about that players potential, just like the people on the old board that insisted on claiming CJ would be an all-star next year...oh wait, then next year...hang on, he just needs another year.
Being a Homer = having unrealistic expectations of a players potential and sticking to that belief despite any evidence/argument presented to the contrary.
As for your other point I agree, Homer is a hilarious cartoon character, but I don't remember Homer Simpson writing anything of great import.