Some people may see that "Deus Vult" is somehow an equivalent of "Allahu Akbar". And then some take it to themselves that they must meme because reasons.
But you see, "Deus Vult" is only ever used in the context of crusades, declaring a battle cry and justifying that it is indeed a "God's will".
Meanwhile, "Allahu Akbar" is a phrase that is first and foremost, used to praise the God ("Allah" is just the Arabic term for "God"; The term is translated to "God is greatest"). It is mostly used either in prayers, as an informal expression of faith, or to express joy with a religious undertone. Unlike the aforementioned "Deus Vult", "Allahu Akbar" was never used in any context associated with a battle cry in history, until now by some extremists that is. It is an equivalent to say, "Hallelujah" that could be used by Christians, Catholics, and Jews ("Hallelujah" means "praise the God"). Though the term is more well known these days for being a slogan by some Islamist terrorists as a hostile taunt meant to spread terror, but the term itself is a positive term associated with prayers and expressions of joy.
People often mistakenly equate "Deus Vult" with "Allahu Akbar". The 2 terms, are entirely different. "Deus Vult" is ONLY EVER used in a hostile context as the sole purpose of the term; "Allahu Akbar" on the other hand is pretty much only hostile in a very niche context promoted by modern day Islamist extremists/terrorists. The former is thus much more offensive than the latter.
Most people just often exaggerate the niche and incorrect negative connotation of "Allahu Akbar" and downplay the actual hostility of "Deus Vult" for 1 reason or the other, though, and thus it would appear to the impressionable that they may seem comparable. But suffice to say, "Deus Vult" is much, much more hostile as a term.
And people who promote the usage of "Deus Vult" as a joke is well, 'hee hee ha ha' stuff, but it is also emblematic of a far greater political problem that I won't go into in this post.