For those who can't see it, that question previously contained things like \hspace{-0.02in}
. Juho edited the question to remove those manual formatting idiosyncracies.
Yes, go ahead and remove those LaTeX commands that manually tweak the spacing in this way. I think your edit was a good one that improves the question, and I think it was fair game. Go ahead and make changes that improve the question. Posts on this site are community-owned; as our help page says, "If you are not comfortable with the idea of your contributions being collaboratively edited by other trusted users, this may not be the site for you." If the original author objects, they can roll back the change and leave a comment to justify the rollback (before rolling back such changes, please be sure that they made the post worse, and do leave a comment providing justification).
Regarding this particular situation, using LaTeX commands to manually tweak spacing and alignment is usually not a good idea. I presume that the original author is doing that to try to tweak the spacing, but this might not be such a great idea, because it won't have the same effect on everyone's machines. The author might like how things look on his own machine a little better with those tweaks, but (a) not everyone will agree, and (b) they can make things look a lot worse for other viewers on other machines. Those commands can cause the alignment to look all messed up for people whose setup is slightly different than the author's (e.g., different operating system, different browser, different MathJax renderer, different screen resolution). I've seen other comments from this author that had atrociously bad line breaks when viewed in my browser, because those comments included LaTeX commands to manually tweak the spacing. So, this is not a theoretical risk.
This is good general advice for using LaTeX in any setting -- you should generally try to avoid manually messing with LaTeX's spacing/formatting, as usually LaTeX knows how to typeset things better than you do -- but it's even more true in this setting, where we want mathematics that will be displayed in a reasonable way for everyone, regardless of browser, operating system, screen resolution, etc.
That said, the stakes are very low. If the spacing is not quite right for some viewers, no one is going to die. If you make an edit and the original author objects and rolls back the edit, don't get involved in a rollback war -- don't roll back their rollback. If the original author rolls back your change and you're not convinced by their reasons, flag the post for moderator attention and let the moderators sort it out. Do feel free to go ahead and make edits that you think are a good idea, but if the author objects, let the moderators handle it. It's not worth causing agita or hurt feelings over this.