What's so hard to understand about "apparently illogical but standardised"? I never said it was beautiful, I said that despite being dumb [^1] at least there is a standard for it (https://refspecs.linuxfoundation.org/FHS_3.0/fhs/index.html). So yeah here are nonsensical directories like /opt, but at least they have a clear purpose, compared to the "well who cares, chuck it in there" approach NeXT/Apple had when tossing stuff around (sure, they've now "improved" that with SIP nowadays, but it's still a mess IMHO)

[1]: for instance, "usr" contains libraries only due to the first PDP7 at bell labs having two disks, the first mounted as /, the second as /usr (user). When they ran out of space under /, they replicated the filesystem structure in their user disk, thus the birth of /usr/bin and the like. When /usr got too cluttered they created /home (or /usr/home, don't recall which)