Because it doesn't have a legitimacy manufacturing process. Left-wing ideology gets constructed and disseminated via universities, corporate employment of DEI/bridge/sensitivity trainers who got educated by those universities; journalists brought up in that intellectual zeitgeist push that message; the agnostic equivalents of the "good Christian women with their puckered, bitter faces" eat it up and inject it into whatever they touch; and so while there are also undeniably grifters on the left, there is still some social "structure" that you must kowtow to, a collective, ever-changing purity test that can be used to tear down anyone who falls from grace or gets too big for their britches.
Conservatism doesn't appear to have such a phenomenon: the closest there is is Trump's scorn/blessing, but anyone with enough gumption can go off and sell their brand of conservatism without giving a shit (and even better, knowing your audience won't give a shit) about whether you become a persona non grata to some portion of the "right-wing" movement (which, again, lacks sufficient institutional centralization to passively enforce and push updates for one "doctrine"). Occasionally sucking Donald's cock (and if you're savvy and contrarian enough, not even that) is an easier concession than staying updated on all the nuances of Palestine/Allyship/Black Worship.
Give me counterexamples to this hot take, if this has any legs I might Mottepost.