I'm not talking about anyone here, btw.
Basically, I don't feel "threatened" by any type, but the type I've had the most clashes with is LSE, and SLI's can frustrate me a lot as well. So Delta ST's, particularly LSE's, must make me feel threatened on some deeper level or they wouldn't be capable of upsetting me as much as the ones I've known have. People watching would be confused as to why their behavior was so upsetting to me if they did not know me well.
On the surface, it would probably appear irl that I have the most trouble with EIE's, but Beta extroverts (more so EIE's) seem to have more of a problem with me than I have with them.