Not sure what happened there.
Leica fans don't attack other brands that make Leica M glass, say Zeiss or Voigtlander. Leica fanatics ... maybe.
On another hand, SLRMagic's fault is probably due to announcing the lens nearly a year before it was shipped. They had some high profile photographers (read: famous, not necessarily great) endorse the SLRMagic brand and especially the 50/0.95 lens early on, but then they just dropped from the radar. Also, their site was (and perhaps still is) very disorganized and lacked vital information. Reaching out to photographers and enthusiasts through forums, social media and blogs is fine, but you need to have some real, factual information on an official-looking site of some form.
It also didn't help them that they were making a very sudden change in brand strategy. Going from CCTV and Toy lenses to a $4000 lens. I can't blame people for not buying their lens, but mindlessly attacking them just because they aren't Leica seems quite immature and unnecessary.
Of course, the fact that there was inconsistency in the design, branding, and especially the quality and manufacturing was not a big aid to their reputation ... at all.