Look at it from a different point of view. If you are a fan of Aldo, hate McGregor, or both, you are gonna be biased. Also, dont just point the finger at McGregor fans.
I like both Aldo and McGregor, but am infifferent on if they win or lose. I have no vested interest in either. With that said, while I understand your point of view, I also see the other side, as well as the bigger picture.
The UFC has arguably never had a bigger star than McGregor. He has the opportunity to do something nobody has done before in holding two titles at the same time. That would be a big deal for anyone. But for the biggest star in MMA to do it would be absolutely huge.
I realize you seem to believe he is doing this to duck Aldo because he is afraid. Couldnt it be just as likely that he is chasing the dream of being the first guy to hold a title in two divisions at the same time, just like he did in Cage Warriors, just like he said he would do when he first came to the UFC? He claimed that was his goal all along.
Now, I can understand why somebody would say its unfair to Aldo. But he is the champ. He might just be called the interim champ. But since we dont know when McGregor will return to FW, if he ever will, for all intents and purposes, Aldo is the champ. If his goal is to be the champ, if that is what he is upset about, then he should go on, business as usual, defending the title. If McGregor never returns, he eventually gets stripped, and Aldo is the champ. If McGregor does go back to FW, Aldo gets first crack at him. So why not defend his title in the meantime? Isnt that what they gave him the interim title for? If he is so upset that McGregor isnt defending, if he doesnt think its fair, why do the same thing to Holloway and other FW contenders?
If its not the title he cares about, if its avenging his loss to McGregor, or even the money that he is after, follow him to LW. If he isnt coming back to FW, challenge him to a catchweight. There are probably other options to fight McGregor other than for the FW title.