We do get that it’s not perfect - we’re looking at ways to improve it at the moment, but there’s bigger problems for us to work on for now, sorry! Hopefully in a month or so we can crack this one.

WHat I don’t understand is that even though I added all the spoiler:s01etc. tags to my visible tags list on my profile, the system still covers them with the spoiler picture. The only way to have it show the real thumbnails apprently is to run a filtered search for that specific tag.
 
So that’s how I browse these days: regular browsing in one window (I just skip all the little “spoiler!” thumbnails) and a search for the specific spoiler (spoiler:s01ep3 etc.) in the other.

While it seems like an outer IF around whatever code handles the blocked tags should do it, there’s a damn good chance attempting to do so would break something.

it would be nice to not have to mess with my tags every-time a new one is added to the default hide list

Right. I think a lot of the default spoilers are a case of better safe than sorry (at Derpibooru administration’s discretion, obviously).
 
Stricken: because copypasting them removed the colon
 
Can’t you just click on the spoiler tags on the settings page to add them to the relevant field? Or am I thinking of something else?

The reason default spoilers exist, is because the default user is assumed to be someone who may want to look at questionable content, but wants to be warned, and doesn’t want to look at porn, or disgusting imagery.

I don’t like that I have to put them in the visibility section, then later clean up.

IDK.  
I don’t even know why you would need that. There’s not a ton of default spoilers outside the episode spoilers.  
But those are supposed to be removed, en masse, 24 hours after the episode in question airs.

Agreed. Adding those goddamn spoiler:s01etc things in this system was frustrating, because copypasting them removed the colon. YAY.