One theory is that they were promised support by someone, maybe that Hezbollah would hit from the north at the same time. Then the videos came out and nuked any possible moral high ground for them, causing their would-be partners to back out. Or the whole thing may have been puppeteered by Russia via Iranian proxy, and Russia's aim wasn't to topple Israel but to divert Western resources there and away from Ukraine.
It goes back to the US intervention in the Moro Rebellion in 1900 IIRC. I don't think Muslim theology is actually so absurd as to dictate that jihadis will go to hell if they get hit with pig fat, they're not sinning if someone else applies it to a bullet.