So, which came first, the chicken or the egg? Do people care about performance because of threads like this or do threads like this exist because people care about performance?
There is absolutely nothing wrong with people basing their choices on getting a better performance, no matter what type or level of content they do. It doesn't matter if it's something they can do on their own or if they read it up on a guide. It doesn't matter if they do it to squeeze a unnoticeable 0,1% or for a bigger gain.
This game has always been and will always be based around numbers, so it will always be a natural behaviour that players try to get the best possible numbers out of it. Some will take it to the extreme, others will take a more flexible approach, but in the end is a power based game with power progression systems. You don't stick around with a tier set from 3 expansions ago just because the bonus effect is super fun, you move on because numbers moved on.
Finally, if lately this has been taken to the extreme for everyone is not because of how the community works, but precisely because of how the game works. You want to end with that mentality? keep it simple. The more complex and unredeable systems are, the more people will rely on sims and finding answers to those questions that they can't solve by themselves.