He could see how this would worry Lord Clarus but that is not a reason to instantly accuse anyone for being a threat.

Interesting to see that Ignis' judgment in any of this is thrown out of the window. As well as Gladio's. If Prompto was any kind of threat, Ignis and Gladio would react back in Crown City, years ago.

"With all respects to Lord Clarus," Ignis says while taking a sip of his drink, "that's bullshit."

...he has nothing else to add. And just continues sipping his drink. Okay, maybe he had enough to untie his tongue to swearing. Sorry.