Well since the Saudis already finance and arm ISIS, I don't think its much of a stretch to say that by dealing with the Saudis we would be indirectly arming ISIS as well.
I mean, its already happened before. Its no coincidence that after
Raytheon supplied the Saudis with 15,000 TOW Anti-Tank Missiles in 2013, ISIS and other Syrian rebel groups suddenly began posting
dozens of videos of themselves
using said TOWS to blow up
Syrian Army tanks and bunkers.