Z-gear:
Often in online forum discussions, unlike 'real world' discussions, there are some major different dynamics in play.
1.) Newcomers walk up & join discussions with strangers. A Sociologist could have a field day with real world cultural norms for small group formation & interaction that get ignored in online discussions.
2.) Often both the topic & the other participants have back stories the newcomer doesn't know. Some folks have already debated the topic on other threads, and pick up where they left off. You have no way to know that back story.
3.) We can't read each other's tone & body language.
4.) We come from different regions & local cultures. We also come from very different backgrounds; Jim Lapenta is an instructor, who thinks about the safety of his students. NetDoc is an instructor and owner to Scuba Board, so he 'represents SB' to some extent. I'm just a rec. diver who likes doing some solo diving and participating in some interesting discussions.
5.) In public online discussions, we're aware we have an audience and often try to market our point-of-view persuasively, indirectly to any section of the audience who might be on the fence, and of course to 'preach to the choir' of those who agree with us. And discredit our opponents' views. Even when people post to you, they're indirectly talking to other people.
Solo adds its own baggage.
1.) Despite some people's assertion of the superior enjoyment of buddy and disturbing risk of solo diving, it obviously appeals to many people.
2.) There's fear people not yet fit for it will get into it, and get themselves killed. Bad for them, their families, dive op.s providing services and the hobby. So if solo diving catches on more, more people will get killed.
3.) Some people seem to have some instinctive negative reaction to it. Even if you provide reasonable assurance that a given solo diver's safety profile for a dive is well within acceptable standards, they're not going to like it. Not just not prefer it for themselves; these people dislike solo diving. It's weird, but there it is.
4.) Many scuba specialties are proudly advocated by mainstream agencies; you 'ought to' take AOW, Rescue, UW Navigation, etc... Solo not so much. I suspect SDI saw that people were going to do it anyway, and decided that a good training program might improve the practice & safety, make some money and distinguish the company. That created some competitive pressure on PADI, since people who normally take PADI courses would jump ship to take SDI Solo (which I did). PADI tried to 'have their cake and eat it, too,' with the Self-Reliant Diver course. They don't even own the name solo! And I haven't seen the course marketed in plain view of their web site. It's like the unwanted step-child.
5.) Given the biases against soloing, some perceive it as an irrationally discriminated against minority, a wrongful (or at least silly) impingement upon individual liberty, and resist this perceived oppression.
Into all this backstory, fairly new divers walk into a forum section, and ask about solo diving.
Richard.