I think without actual access to the material it's pretty hard to say. For example, the report highlights that someone commented with nothing but a series of Palestinian flags to someone's post, and their comment was flagged and removed. However, they don't share what the original post was; responding with a series of Palestinian flags to an Israeli hostage relative's post about their kidnapped sibling, for example, would be clear harassment and abuse. (And these kinds of abusive comments are extremely common.)

The report also has some pretty strange language, like mentioning that a post which was flagged for nudity contained a picture of a dead woman, and a fully-clothed man holding her body. But... There are so, so many pictures of fully-clothed, male members of Hamas holding nude or partially-nude dead women they abducted and/or raped before murdering. Why does the report only say that the man was fully clothed? Maybe it's just a grammatical error, but they're really light on the details, and releasing the underlying data would answer a lot of questions.

Personally I am suspicious of HRW's report, since they've been caught releasing misleading reports in the past, and the director of HRW's Israel/Palestine division is a BDS activist [1]. Obviously your viewpoint may be different, but without access to the underlying information it's pretty hard to make a compelling case to either side... Which to me points to the report being more worthy of suspicion, since if it was clear-cut, they'd easily convince more people of their correctness by releasing the data.

1: https://www.ngo-monitor.org/fact-sheet-on-omar-shakirs-bds-c...