The House Intelligence Committee is not one of the most powerful House committees—like the Appropriations Committee, which decides how the federal government will spend $6 trillion each year, or the Oversight Committee, which can investigate anyone it wants to investigate. Nevertheless, it is extremely prestigious because its members are briefed on all manner of confidential things that other House members don't get to know. Being a member makes a Congresscritter a true insider. Slots on the Committee are highly desired and getting one is a big plum.
So when Mike Johnson gave a coveted slot to Freedom Caucus member and all-around firebrand Rep. Scott Perry (R-PA), it set off a lot of alarms within the Republican caucus. In particular, Republicans already on the Committee were shocked, but their shock turned quickly into rage because members get access to national security secrets and there is a long-standing tradition of bipartisanship when handling anything that affects national security. Seats on the Intel Committee were previously granted based on the ability to keep secrets and work across the aisle. Intelligence Committee member Rep. Dan Crenshaw (R-TX) said of the appointment: "It upends the meritocracy that has long been the defining practice on Intel." Then he added: "The speaker needs to remember that there isn't only one group that can threaten him. Just do not teach the lesson that the only way for us to be effective here is threatening, because I'll take the lesson and I'll do it."
Other Republicans said (on background) that rewarding hardliners like Perry will only encourage more antics, like tanking procedural votes, blocking bills, or making motions to vacate the chair. A large chunk of the Republican caucus is very upset by Johnson's caving to the Freedom Caucus. It is worth noting that none of the Democrats' most pugnacious members are on the Committee. (V)