There seem to be three questions here:
1. To what extent can we lump Reform and Conservative together? Answer: no way. I used to be Conservative. Conservatives by and large respect halacha, just don’t keep it. Reform are another story entirely. The whole point of Reform was to reject halacha and being separate from mainstream society, i.e. radical assimilationists.
@. Are most Jews in non-Orthodox circles halachically Jewish? Depends. Conservative, probably still the majority, but better check. Reform – iffy – the real assimilationists drop out after a generation or two, but there are plenty of intermarriages. So – better check for sure. Non-affiliated? Anything goes. Check back three generations.
3. Conversions. By Orthodox standards Conservative conversions can’t be al pi halacha because if nothing else the witnesses aren’t shomer Shabbos and therefore aren’t kosher. Of course, the converts themselves are usually sincere, just ignorant. Conservative converts tend to be fairly well educated. Reform conversion classes seem to be a joke. BTW Conservative rabbis might get a little frustrated, because most serious Conservative converts eventually go on to convert and practice Orthodox. I know one person who went through four conversions – Reform, Conservative, Modern Orthodox and Hareidi. For those FFBs who think so highly of themselves, would YOU have had the mesiras nefesh to do this? I feel privileged to know this person.
The bottom line: NEVER put ANYONE down. No one gets consigned to any junkyard here. You can’t be oiver ahavas Yisroel (including Reform and unaffiliated) and get away with it long-term. And for non-Jews you have to have kavod habrios. HaShem has plans for us all – Orthodox, Conservative, Reform, non-Jew. So let’s stop name-calling and start working on doing our job.