I don't really feel that the frog forums hurt the site or detract from the caudate portion. As it is, the other amphibians section receives much less attention than most areas of the forum anyway. Lots of forums have "Off Topic" areas; at least frogs are almost related to the subject matter. I can see how you wouldn't want frog specialists coming in and ignoring the caudate section, but that's really not been happening. At the very least, the other amphibians section serves to point people interested in them towards better sites to discuss them. Given the recent influx of people to the site that are just beginning to keep caudates, it's reasonable to assume many of these would like to try keeping frogs as well. It's no sweat off our back to point out that you shouldn't keep that new pet in a heated aquarium, and in other cases, educated discussion about other amphibians can't really hurt either.
Regardless, the site's been growing, and if you take the other amphibians area away, people will still post about them on the caudate section, and moderators will have to delete them, leading to misunderstandings by people that take things way too personally.
It's a lot like the fruit flies in my apartment; I provide an open jar of media near the sink so that they can be contained in one area and dealt with properly.
Should the other amphibians area cause problems with the main sections, or take from the emphasis on caudates, then sure, they should be removed. However, I don't really see that happening at this point, so I vote "yes."