I realize this is all tongue-in-cheek, so...
Absence of evidence does not constitute evidence of absence. Likewise, ignoring the subtitle of the entire series deliberately excludes evidence vital to assessing the thesis of "Friendship isn't Magic" and therefore diminishes its validity.
Consider, if you will, that nopony explicitly claims Princess Celestia is an alicorn in the show itself. That doesn't mean she isn't one. What's more, we know through such authoritative sources as Sabrina Alberghetti that the production staff refers to her and Luna as alicorns. As those who make the show, they bear the official authority of indisputable canon.
All the more so in the case of "Friendship is Magic".
We know that this subtitle was bestowed upon the series by none other than than the Creator Herself, God-Empress Lauren, Ultimate Best Pony. It would be no less than a sin
to suggest the Goddess and Mother of All Ponies did not speak sooth when naming the show.
Ergo, forthwith, heretofore and in accordance with the established legal doctrines of ipse dixit, ipso facto
and presto change-o,
we can confidently assert that Friendship is indeed Magic, stands as such under Equestrian law, and that declaring otherwise violates said law.
Therefore I so move, as the law clearly demands, that the heretic Blue be banished from Equestria, and thrown in a dungeon in the place he is banished to.