There are many people for whom this is complex, you're assuming a foundation that not everyone has. There are also many people for whom nothing is complex, they assume they can understand everything, while they don't currently, they assume they'll be able to learn it without issue.
Dealing with new starts who are straight out of education is often like reading posts from 4chan.org/b, at first you don't know if they're joking.
It's not all doom and gloom, occasional I'm pleasantly surprised by the calibre of those beginning their career/hobby, but this is the exception.
But there's also nothing crazy about a company saying: for this role, we expect the candidate know linked lists. It's not esoteric and I think a lot of us would consider normal programmers who have had to write linked lists (and other data structures) for one reason or another.
Personally I agree, however I know people employed to code PHP who have no concept of this. Some apprentices who have left college have joined our company who don't know this.
There are many people for whom this is complex, you're assuming a foundation that not everyone has. There are also many people for whom nothing is complex, they assume they can understand everything, while they don't currently, they assume they'll be able to learn it without issue.
Dealing with new starts who are straight out of education is often like reading posts from 4chan.org/b, at first you don't know if they're joking.
It's not all doom and gloom, occasional I'm pleasantly surprised by the calibre of those beginning their career/hobby, but this is the exception.