Because he's trying to peddle this narrative that anyone that doesn't like Ange's football is a Dyche fanboy, and is less enlightened than him.
All things being equal, I'd agree with you on the bolded - I think the issue is that a lot of this conversation is driven by the narrative between Ange and the media. He's been married to his system and his way of playing quite consistenly (except for the last few ties in Europe) and has shown very little flexibility, which he's been called out for by journalists and in response he's been extremely rude and condescending in interviews. If anything, the fact he's won a trophy by adapting and dropping his rigid approach kinda vindicates the media that had been calling him out, and the fact he's being arrogant about the victory, and having an "I told you so" moment, could be a bit grating for some.
I don't fundamentally care, the media are bastards anyway, and it doesn't change my view on him that he's a nasty piece of work, but I can understand why it's worthy of discussion.