Hm. I think Dabi is inspired by Stain to the extent that he believes hero society is corrupt and needs to go down, and I also am not sure how much of the details of Stian’s fight with Izuku Dabi is aware of. However, Dabi also has personal motivations as his fight with Endeavor showed us, motivations that we don’t know if Spinner has at least not to the degree Dabi does (esp if Dabi is Touya).

That’s actually another reason why I would find it interesting if Dabi is Touya, because he would be more likely to go along with Shigaraki perhaps because, well, the League of Villains is kinda starting to resemble a dysfunctional family of its own in a few respects, which might explain why Dabi is less likely to protest than Spinner at least from what we’ve seen. I also think that whatever Dabi’s personal grudge is, as I said above, might also contribute to his “burn it all” tactics. 

Dabi like Stain believes his actions are morally right because the ends–exposing hero society’s wrongs–justify the means. We know from his breakdown after his fight with Endeavor that he does indeed feel guilt about the families of those he kills, but he also believes it’s necessary. 

In many ways this is kind of terrifying because he is so certain he’s right he’s willing to inflict a pain he appears to know personally on someone else. It sets up a conflict between Dabi’s ability to empathize (which he does have) and his stringent ends-justify-the-means philosophy, which is probably going to hit him at some point.