I don't know if extinguishment relations are actually the worst in general, maybe for other types it's super-ego, business or conflict relations, but for me, EIEs are worse than SLEs.
EIEs do feel like my complete opposite in a way that they don't value what I do at all despite being good at it. And for me, it is worse for a person to be good at the same things that I am yet reject them as unimportant, than not to value things they're not even good at in the first place (like SLEs or LSIs). Also, with Beta STs, we rarely even meet because we're so different, and when we do meet, it's easy for me to just ignore them if need be, or simply stay on a superficial level and not go deeper. Heck, I actually have an SLE friend and we're doing fine.
But EIEs? Just like any other NF type, it's much easier for me to meet them. And when we do, it's harder for me to run away from the feeling of being judged all the time, for not being... more like them, basically, or more beta-ish in general. For being too sensitive and too serious for their taste, for not enjoying and not participating in their kind of humour, for being a party-pooper, I think that's how they see me, in short.
This is not to say that EIEs are bad as people, or that I resent them, or that I hate them. It is only to say that I think the EII-EIE relations, of any kind, may be much harder in practice than the theory paints them to be (yes, to the point of being equally bad or even worse than conflict relations). Sure, personal maturity plays a huge role, but still.
I wonder, too, is there any EII here with similar thoughts?