In what I'm sure will be a shock to MAGATs, there's actually law, formal process, and guidance from the Secret Service that determines what candidates receive secret service protection. (And nowhere does it say, "because a dropout from the Democratic Primary whines a lot in public", much as I understand whining is incredibly popular with MAGATs.)
(...)
Kennedy doesn't qualify based on the existing guidelines. If MAGATs really think he needs Secret Service protection, they should tell their leaders Mike Johnson and Moscow Mitch, who can act on those concerns (including making them public, should they deem it necessary).
But it looks like these requirements are too high. The extent to which the U.S. system builds barriers for candidates who do not belong to the two major parties is pretty problematic from a democratic perspective - not just in this regard, but also when it comes to ballot access.