Do you really think these guys could avoid being taken down by a top level grappler?
Nope, but I haven't seen them claim they could either.
Do I think they could avoid being taken down by a BJJ white belt or a low-level wrestler or a random grappler of the caliber they are likely to encounter in a street self defense situation long enough use their striking (or draw a weapon)? Sure. Unlike the practitioners in some of the other "anti-grappling" videos Hanzou has posted, these guys seem to at least understand the basics of how takedowns work and how to realistically counter them and they seem to understand the importance of pressure testing. They may not be ready for the UFC, but their takedown defense is probably adequate for most street scenarios. (I'm just guessing here, because Izzo is the only one of the bunch I've seen actually practicing live, but I'll give them the benefit of the doubt.)
Now, if they were touting the techniques they demoed as a magical talisman that would enable strikers to "fear no grappler", then I would agree they were being ignorant, arrogant, and disrespectful. I didn't get the impression that was their intention.