As usual, the headline is hyperbolic and doesn't match the substance of the article, which is mostly correct.

RLUIPA governs the prison as an institution. The prison itself tacitly admits that the legal risk here was a matter of policy. As the article says:

    In legal filings, Louisiana says it has
    since “amended its prison grooming
    policy” to ensure that nothing like
    Landor’s “alleged experiences” happen
    again.

So Landor has two options: (1) He can continue with his RLUIPA claim but against the prison; or (2) he can try a §1983 suit against the guards individually.

Option (1) is what he should have started with, and the fact that he didn't is indicative of bad legal advice for exactly the reason the Supreme Court explained: RLUIPA on its face clearly and textually only governs state institutions receiving federal funding, not individual employees in their personal capacities.

Option (2) is unlikely to prevail since there is probably no case law on point (most claims of this nature proceed under RLUIPA because it requires strict scrutiny of burdens on sincerely held religious belief, as opposed to the First Amendment analysis requiring mere rational basis for generally applicable state actions that incidentally burden religious free exercise).