I found this on a website from Malaysia...
1. Why is it called "building" when it is already built? For instance, "Hey, look at that tall building over there!"
2. Why does the person who manages your money called "broker"? Is he broke?
3. If infant is enjoying infancy, why can't adult enjoy adultery?
4. If horrific is to describe something horrible, then does terrific describe something terrible?
5. If people from Poland are called Poles, then does people from Holland called Holes?

I realize this is meant to be a bit of language humor, but, "terrific" originally meant "producing terror." The Word Detective says<blockquote>Quote
<hr>“Terrible” first appeared in English in the 15th century, “terrify” in the 16th, and “terrific” in the 17th, each embodying a serious sense of fear in keeping with their roots. “Terrify” has kept its original meaning (albeit with diluted uses, such as “Timmy terrified the other children all afternoon”), and “terrible,” while often applied in a hyperbolic manner (”That’s a terrible haircut”), largely retains its connotation of something really bad. But “terrific” moved from meaning “causing terror” to meaning simply “severe” by the early 19th century (a sense still heard in phrases like “a terrific blow”). This change apparently weakened the connection to actual fear enough that by 1930 “terrific” was being used as the colloquial equivalent of “great” or “wonderful.” It’s an odd change in meaning, but probably just as well. Otherwise, “Gee, your hair smells terrific” would have made a lousy advertising slogan.<hr></blockquote>

"awful" which used to mean "awesome" changed meaning the other way.
I don't see why "Look at the building" is any weirder than "Look at the structure" or "Look at the construction."
A broker was apparently originally someone you hired to broach (break open) a subject with another party. So it is related to broke.
And actually I've heard that adults do occasionally enjoy adultery. A better question might be: if that's so, why can't infants enjoy infantry?

maybe english is a weird language. and something that perhaps supports that theory is that the examples on OP's list could only seem 'weird' to a non-native speaker or, at a stretch, a native speaker with a very limited grasp of the history of the language.

My sign off on another board is a quote I got years ago in a letter. I don't know the provenance, sorry.
"English doesn't borrow from other languages. It follows them down dark alleys, knocks them over and rummages in their pockets for loose bits of grammar."
Ed

#5 - Nice quote, although I would say English is usually after vocabulary rather than grammar.