Is Messianic Judaism Christianity or Judaism?

[Okay, maybe Mike Johnson is a competent parliamentarian.]

Christianity, and anyone saying otherwise is acting in bad faith.

Yep. If it were a form of Judaism at least some other Jews would recognize it as such. As it happens, next to none do.

[Okay, maybe Mike Johnson is a competent parliamentarian.]

Saying that Messianic Judaism is Judaism is like saying that Christianity is a form of paganism, since Christianity has adopted some pagan ideas.

It would make more sense to say that Christianity is just a Jewish sect, which is what it was to begin with.

Another similar belief would be that Jainism, Buddhism and Sikhism are merely Hindu sects, but I think that would be false.

What do you think makes that falser than the equivalent take on Christianity? Christian orthodoxy on everything from the nature of God to the specifics of moral theology is at least as different from Jewish orthodoxy as Buddhist orthodoxy is from Hindu orthodoxy.