The "both sides" thing is political positioning like @RunsWithDinosaurs says. Apparently the Cass Review was subject to unpleasantness from both trans activists and the "gender criitcal side", but if you look at the actual concerns in terms of what the Cass Review were looking at, it's clear from the final report that the toxicity that was relevant to the report itself was directed at medical practitioners being subject to horrible abuse when they would question any aspect of gender identity ideology.
If you read the final report itself, you'll find that there are many language choices that were made to appease the trans activists, and there are other choices too, for example it does seem to have taken for granted that everyone has a gender identity and its congruence with sex or otherwise determines whether a person is trans.
In spite of all this, the fact that the Cass Review happened at all, and has made a stand in support of gathering good evidence and using that to decide on how to best treat children and young people are massive positives.