I used to vehemently oppose SEOs but now I tolerate the idea of moderate use. In theory, stretching the fascia through the use of SEOs would be a great way to break a genetic barrier if you had a lagging part. However, the sad thing is that it's incredibly abused and misapplied.
I have put serious thought into injecting synthol or other SEOs into my calf, as I damaged it in a biking accident. I have really good calves but one part of the muscle receded slightly. I'm very confident that a little SEO could go a long way. The ugly part of SEOs is when people apply this logic to EVERY muscle group, and then employ their theories and go way overboard. That's not cool.
If you think about it, many more people abuse steroids and take obscene amount of non-steroidal supplements than SEO abusers. It's just that SEO abuse is a lot easier to gauge visually. You cannot visually audit a gym, do a sweep of the room and conclude how many guys burned a hole in their wallet because they buy too many supplements. Heck, you probably can't always tell how many guys are abusing steroids because some of those knuckleheads don't even look like they work out! LMAO!!!
I'm not here to defend synthol or SEOs though. I think they can be used responsibly, and the only responsible use in my eyes is extreme moderation. But we all know that hardcore bodybuilders are hardly the moderate type when it comes to substance abuse (generally speaking). Again, if I ever used it, it would be because one of my muscles is physically damaged. I've managed to balance out my calves very nicely but in my eyes it's a glaring imbalance and I wouldn't reject the idea of using some sort of SEO to correct it, probably not synthol but who knows... it's not something that occupies my mind at this time.