I can think of several feminist regulars who have had massive run ins with other posters on this board. Some have received absolute pastings! Hasn't stopped any of them posting though.
I like the extreme views. Without them what is considered moderate would be a lot less pro-woman. The better the arguments defending the extreme radical viewpoint, the harder it is to let any maltreatment of women go through, even though the consensus opinion may be much more moderate.
How much would feminism achieve if the most radical feminist position was "women should demand equal pay but we accept that we'll have lower salaries because we 'choose' to sacrifice our careers for children and it's only natural that employers will be suspicious of this and promote men instead of women". OTOH try arguing for free childcare and mandatory life imprisonment for all DV abusers and you might not get that, but you'll get something a hell of a lot better than accepting the status quo. Personally I have found that what seemed extreme to me when I first started posting on here now seems perfectly obvious. 
I would agree that if you don't want to get a bashing on the feminist board it is definitely worth lurking for a while. You only have to learn a little about feminism to realise that there is a mainstream view most feminists have on things such as porn, DV, glass ceiling, etc. while other areas have a lot more room for disagreement. I learned all this just by lurking on this forum for a short while. You don't have to read lots of books and the internet is quite good if you need a quick brief synopsis.
It can get very wearing to have to explain accepted feminist 'rules' (e.g. that the patriarchy exists) over and over again so posters tend to refer to arguments in shorthand or assume that the premise is a given. It's no different to the shorthand used in special needs or any other specialist area, and if anyone asks politely about it one poster will always take the time to explain or to point someone in the right direction.
I don't see this as a problem. I think it's about respect. This is a feminist forum. I wouldn't wander into a race rights forum and start posting without first making sure I was wasn't saying something offensive and controversial, or, if I didn't have the time to check, I would admit that I didn't know much about the theory and was prepared to be open minded but I think this... and then ask politely for opinions.
The trouble is when people post POVs that they haven't really thought through. If they do so in a "what if" kind of way then people tend to be ok with them. However, if they post in an aggressive manner and fail to fully defend it with facts and evidence they will get torn to shreds. Some people when faced with supporting evidence change their mind quite radically. I have. Then you get those who get defensive (on both 'sides') and start vehemently defending their position at all costs. But that's down to personalities, nothing else. It has nothing to do with whether you're a feminist regular or new to the board and this takes place across the whole of MN, especially on AIBU.