yes, they are case insensitive... i think the rationale has to do with spoofing opportunities with case variations
also, this is a big struggle with me also, i wish there was long form decent clients, but i don't think there really is, and i have zero confidence in the devs of yakihonne or pablo, the highlighter dev, who is doing a thousand other things than maintaining his bastard child highlighter
and i also, as i say, strongly disagree with the idea that kind 1 posts should not render markdown, this is complete patent nonsense