Thanks for the detailed reply Dirty.
Klecser,
It sounds like playing it against humans probably isn't for you. Sins has its share of jerks and its share of helpful friendly players just like any other game. One thing I have noticed about Sins is that people have a much greater emotional investment in their performance and in winning than in FPS games, which makes it easier for people to lash out at other players on their team who they feel contributed to a loss or who they feel might be compromising the team.
This makes sense, as there is a significantly greater time commitment required to set up a cooperative RT4X than an FPS. This is part of the reason why I like RT4X's though. There is more of a balance between strategy and tactics, as opposed to FPS' which tend to be more tactics oriented.
It really does require having a significant amount of free time so that you can play a couple times a week in order to acquire skill. If you only have a few hours a week for Sins then it's probably not for you unless you want to try to play against newer players on vanilla Sins, which is still possible.
Sure. I'm not looking to become "good" at the game and I have no problem losing, so long as the frequent losing is a learning experience each time. There is nothing I hate more than a silent experienced player or one that isn't very tactful in giving their advice. I can have a lot of fun while losing if the other player is a "good winner" and a good sport about it.
Ultimately people need to develop an adequately thick skin to play any humans v. humans game in online multiplayer. However, this really shouldn't be a problem for people. If you allow people who live 1500 miles away to get under your skin by typing snide comments in a silly computer game, then you may have self esteem and confidence problems which are far more serious to worry about.
Trust me in that my self esteem is in no way impacted by snide comments on the internet.
I've been around for a while and I've participated in detailed discussions of competitive miniatures games online. I know all the types. But given that my time is now limited, I have no desire to even get involved in those sorts of experiences. So, at some level you're correct that it may not be right for me. I wasn't trying to go off topic by commenting. As an "outsider" I frequently like to remind vets of games that there are frequently very logical reasons why many gamers, both casual and competitive, don't choose to play the "metagame" of online gaming. 
It's hard to put a number on it. There are many experienced pros who like to offer advice to new players. Then there are some who aren't as friendly and as welcoming and understanding. I'm not sure what you mean when you say that you have been burned nor exactly what you're trying to ask. Are you asking, "If I play against other people will be picked on and will people make snide comments?" or "Will other people be nice and not try to steamroll over me and beat me badly?" The answer is probably Yes and No, respectively.
The first one bothers me, but not because I'm offended personally. It bothers me because I hate the the fact that you can get away with stuff on the internet that most people wouldn't have the balls to get away with IRL. But that's the nature of the system. The second one bothers me, not just because I'm beaten, but because frequently a vet in any game will steam roll a new player, say "gg" and just leave. No tips, no nothing. I don't have time to do my day job when I'm recruiting and I resent the fact that in online gaming you practically have to if you want any sort of depth. Some communities require less than others, and so I asked knowing that I'd get some truth, some lies, and some answers that people don't really understand what I'm asking. You seem well spoken and very knowledgeable and in the time I've lurked I've only seen positive contributions from you, so I take this as more truth. Other members on here will level the classic "get tougher noob" that is so characteristic of the socially inept gamer mentality.
The only way to get good at Sins is to acquire a lot of experience playing against other people which means losing regularly and often. (You have to see the tactics other people use against you in order to learn them for yourself.)
Absolutely. I've gamed competitively (just not Sins) so I understand this.
For example, last night in a 1v1 a newer player (who had about 80 games under his belt) confidently jumped his fleet onto my fully upgraded Vasari starbase backed up with a sizable fleet and phase jump inhibitors. He couldn't believe I was able to do that. (I don't know why; there's nothing unusual about that.) He then surrendered. The lesson? Don't send your fleet in to a known hostile gravity well without scouting. He just learned a lesson--the hard way. (I also learned this very same lesson two years ago, the hard way.) Experienced players will generally offer advice if you ask nicely and we have an entire forum full of threads about strategy.
I've definitely learned the importance of scouting in playing just the AI.
Thanks for the advice. Regardless of how I end up on this issue, I hope that your response helps new players to think about what is necessary to really improve. I hope vets are reminded that a player base is always dependent on new recruits, which you can't get without a proper social investment from vets.