I think the harm here is for other threads on the same core that share the same queue of in-flight loads.

Coherence wise it won't interfere with other cores and their access to memory.

That said how hyper-threads share CPU resources is a moving target. My understanding through hearsay is that in the past many resources were statically partitioned with hyper-threading enabled, but now things are moving towards allocating resources dynamically which means that a thread wasting resources would be sucking up capacity that could be used by another hyper-thread.