Half the entries detailing things that could destroy mankind or the entire planet or the universe or whatever seem to end with "Oh well it was only playing with us now we made it MAD!" Very spoopy indeed but that's not the track record you want your we can do anything we want organization to have
imo that's mainly due to SCP's writing getting extremely shit, it's the same MOAR POWER AND BIGGER crap hack writers often do (*cough* star killer base in TFA). originally the foundation was more of a background entity with enough ambivalence to keep your suspension of disbelief intact (somewhat) with much more grounded/curious SCPs, then slowly every SCP had to be BIGGER and WORSE and WORLDENDING; combined with the average fanfiction-tier need to "explain everything", even if it made everything worse and more illogical, in part fed by bad writers trying to create their own scp cinematic universe.
it's one of the reasons I don't really like scp-3333 (tower) for example, even tho lot of people consider it a "better" one. I had a whole wall of text prepared a while back but couldn't be arsed to post it yet, but for example it doesn't make sense for the foundation to constantly feed it scientists, MTFs or even d-class (even if the idea was to base it on some failed ww2 operation where it happened, but that was during a war).
the foundation, as big as it is, is still limited by basic bitch supply and demand, it's simply not feasible to waste personnel on some SCP that's not even a threat. remember it's "secure, contain, protect", and while there's certainly a need for research and to figure out what "makes it tick" (although that more often than not leads the overexplaining I mentioned above), it still needs to make sense.
take scp-087 (the stairwell) 3333 is based upon. what does the foundation do? use a few d-class, then they figure out all they have to do is lock the door and throw away the key, that's it. part of the reason it also works that well
because it's not explained (much less than 3333 for example). simple, to the point, memorable.
meanwhile you have 3333 that doesn't even have a scientific approach (what happens when you open all the trapdoors, what do you see? what happens on the lower floors? who were the people you could apparently see? where do they come from?) nor even logic, because overly explaining "the monster" it inevitably leads to "so wait how the fuck does that even work? what do they eat unless someone is dumb enough to climb up? where do they come from? how did they evolve?!" asf.
and the most annoying part (getting back to shit writing) you can't fucking tell me the foundation, with the experience it has, would just a) feed it more personell b) wouldn't vet said returned personell at all. ffs people got put in quaratine for the fucking wu-flu, 3332 other SCPs and apparently the foundation never ever considered the possiblity of skinwalkers or any other ill effects.
like I said, whole wall of text, but those are the main points.
TLDR: it's shit writing.