Interesting anecdotal response - the 1st time I did Kogane Castle we wiped on the 1st series of trash mobs (yeah, we sucked :P). Then again on the 1st boss, and again on 2nd boss. We eventually got through and completed the dungeon, but it was a group of 4 'new' players (what are the odds of that? lol) all in quest provided gear. It was not 'cakewalk easy', but we still had fun as we chatted and joked as we did it... even with the wipes and problems we had. We did not find it "easy" to do, or a cakewalk that we could sleepwalk through.
But does that mean it's too hard? No, just as your anecdotal comments about forum posters saying it's 'easy' doesn't mean it's dead easy either. It might be easy for you and others of decent skill, or those without disabilities... yet that doesn't mean the content will be easy for everyone, and vise-versa.
So again, what you're doing is the exact same thing I talked about - your referring to comments on the forum to back you up, yet a games forums is a minority of it's player's. Most players never, ever visit or post on a forum... it's usually the high-end players and/or 'invested' players (regardless of skill) who visit and post. Yes, you do have casual's and lower-skill people here, but the vast majority of ppl posting on forums are those interested in lore, improving themselves, doing well, being as best skilled as they can, etc.... thus post's on here about how easy something in the game are... is biased towards the higher-skilled players, and not the norm.
BTW - it's been stated by a few MMO dev's about the low rate of visiting to official forums, so it's not something I'm just saying. For instance years ago Blizzard confirmed that only around 15% of their player base had ever visited the official WoW forums at that time (iirc it was back in 2012 this was said). LotRO dev's confirmed similar number's for their forums. I believe STO dev's also had the same to say at some point.
You are correct in that there are many sides to the coin - in regards to how easy/hard some content is, the claim by some that many people do not want to get better (this is true, many ppl don't care to improve.. they just want to log into a game and play without any thought of improving or such as they find the idea of that as 'work' and thus stressful, and they play games for 'fun' and don't find it 'fun' to min/max or such), how people view things due to the people they associate with, etc.
But as pointed out as well, we do not have the metrics - we do not see how many times dungeons/trials are failed, or how many times groups wipe, or how many times ppl clear content on their 1st try... or whether they are in groups of other new players to the content or with experienced well-geared players, etc. Fact is we can only go by what we read on forums, what we see in game, and what we see friends/FC's/map-talk talking about.... and all these things are biased as this limits the extent of the knowledge we have and causes a skewed view of things... because the vast majority of ppl playing the game won't speak up, they do not post on forums, they don't speak on map/zone chat, they likely aren't in a FC, etc... so you'll never see/hear their stories of struggle, woe, or success.