There are countless fields of philosophy, and in each one you will find academics passionately pontificating on all sorts of questions. But you won't find many people actively arguing that a field is fundamentally wrongheaded, that philosophy isn't relevant to a field, or that a field should be left to others. I contend that this is due to self-selection bias: only the people who think a field is worth philosophical study bother write about it, while other philosophers leave them to their own devices rather than expend time and resources trying to debunk the field - that would be a fast way to lose friends and goodwill. But this then gives the false impression to onlookers that philosophers as a community all accept at least the relevance of these fields. This can then be used as ammunition by anti-philosophers, who can pick the more ridiculous fields and laugh at them. This is unlike in (some of) the sciences where new paradigms are nigh-universally accepted to supercede old ones.

Edit: This isn't to say no philosophers ever wrote criticism targeted at whole fields. They do, it happens. But only very occasionally, and you will have to dive deep into the archives to find it, because it is always vastly outweighed by the amount of research in the field, and at any point in time it will be almost impossible to find any active research being done to debunk fields as a whole.