"House Intelligence leaders" are not exempt from hysteria.

Indeed, that's an obvious appeal to authority fallacy, and "appears increasingly likely that a foreign adversary is behind some cases" is just weasel words; it's vague and meaningless but articles like this position it as pretty much factual.

Sure, they don't explicitly say it's a fact, but it's enough for many people to be "sold" on the idea that it's foreign adversaries.