I think I know which forum you're referring to (I've struggled with an ED for years as well) and I agree. In my own experience I find that there are a lot of things that you can be open about over there, but if you do so much as even imply that you don't want to live with all of this pain and suffering anymore, people often jump all over you with the typical cliches and platitudes when they really don't know just how much you're actually hurting.
I've never personally talked about it over there because... well, I know better and learned that the hard way after a few awful and even traumatic experiences irl after simply being honest about how I was feeling (as sad and fucked up as that might sound), but way back in 2015 I saw a bunch of people band together on someone's thread and try to track the OP down, figure out their location and contact the local police because the OP wanted to let people know what most likely happened with them IF they didn't come back at some point in the future. I understand that it doesn't come from a place of malice in this case and that these people seem to genuinely believe that they're helping (and not potentially exacerbating the suicidal person's suffering, feelings of being misunderstood, etc, or otherwise making their life even more difficult than it already is), but you definitely do need to be more careful with what you say over there if you're serious about your plans and don't want people potentially messing with them (at worst), or giving you the same old cliches that you've heard a million times (at best). I've found a lot of comfort in that forum as well over the years and some people over there really do seem to get it, but overall, SS is definitely the least judgemental and more compassionate forum of the two, in my opinion.
Also, I'm so sorry that you suffer from an ED. They are absolute hell and my heart goes out to you.