"Other" forum doesnt necessarily mean a negative comment, it can mean just what it says, as in "something I read on the other forum" could just mean the same as "some I read on another forum" its just being a tad more specific as referring to one of the other large scale forums, sometimes it can be hard to determine just which "other" forum they are referring to, afterall their are several others, Garden Railways, LSOL, LSC, Gscalemad, several dozen (it seams) Yahoo forums, not to mention manufacturer based forums like those hosted by Bachmann or Aristo, lets not even go into all the personal blogs.
Now sometime the way one reads the use of "other" could be seen to be in a negaitve tone, but mostly I read its ment more as a neutral tone, a way of saying I saw this elsewhere without specificly naming the "other" forums, as in the past their have been issues where one forum did not prefer to singled out in comments on another forum. (not here mind you) I think this is why most simply use the generic term "other forum" instead of specificly naming another forum simply to avoid potential conflict, as most of us are active on more than one forum, and a few are active on just about all of them, and all of us want to maintain a good reputation with other users.