Lightning routing node operators can charge higher fees for that, and incetivize others to run their own nodes.
Unless I missed something you can't charge fees for incoming channels so you also can't charge
higher fees for that use case. You could charge higher fees in general, but I don't think you get to set different fees depending on which channel the balance comes from.
But Lightning nodes charge fees if transactions are routed through them right? Then if there are high enough entities who are holding UTXOs they don’t like, demand will rise and therefore fees will rise. Unwanted UTXOs can merely be routed through Lightning, and leave those unwanted UTXOs with the routing node.
Observers would call this mixing, I believe it is increasing the anon-set.