OP is talking about (mostly) TATP here. It's very easy to make, harder to detect with traditional methods and potent enough to be a problem. It's also hilariously unstable, will absolutely kill you before you achieve terrorism, and if you ask people on the appropriate chemistry subreddits how to make it you'll be ridiculed for days.

Yes, peroxide chemistries famously don’t show up on a lot of explosive scans. TATP is an example but not the only one and far from the best one. They are largely missing from common literature because they are too chemically reactive to be practical e.g. they will readily chemically interact with their environment, including most metal casings you might put them in, such that they become non-explosive.

That aside, TATP is a terrible explosive. Weak, unstable, and ineffective. The ridicule is well-deserved.