That's a very common question for people new to competition climbing. Route setting for competition is in general quite different than for "regular" gym routes. Route setters at comps have several, sometimes conflicting requirements, which also vary depending on the round (quali, semi, finals):
Nothing more unnerving than having competitors tied and needing to resort to previous round to resolve the ranking.
New and diverse problem types
You don't want to do problems that the competitors do every day and you need to have difficulties for all kinds of body types to prevent an advantage for one. Often at comps special holds or such that aren't yet commercially available are used.
You have a live audience to capture and on a bigger scale, promote the sport. It is especially important in finals, that's why often finals are a bit easier and potential more straight forward than quali/semi. In an ideal final, all these points are fulfilled
- Suspense: The winner is decided on the last boulder.
- Tops: Every problem is topped at least once to showcase every move.
- Circus: A great climbing problem isn't necessarily great to watch. That's part of why you see huge dynamic moves, 360° campussing, ...
All of this means that there can't be any strict rules. There is a big team of route setters at work and to try and fulfill all of the above points (and probably more I am not aware of/didn't think about now). Their routes also aren't set in stone: They obviously set their routes in advance, but they adapt routes in between rounds to adjust them to how the competitors are performing.
Also modern style (well it's true for a while) competition bouldering is focussed on big volumes. Sure there is always a slab in there, but you see almost no steep, crimpy, teeth grinding boulders. That's partly for spectacle and setting uncommon problems, partly to prevent finger injuries. Meaning they are hard to compare to "normal" boulders. You probably expierenced that in a gym too: Big unconventional routes don't necessarily fit in your personal route ranking, because they might not suit you. That's generally true, but much more so in those kind of routes.
There is no such thing as a minimal grade in comps. Setting comp routes is an experience base art and a kind of "shadow-competition", trying to get the perfect set of routes to the wall to cater the competitors and watchers needs.
Note about lead:
Most points also apply there, but as there is just one route and one attempt per competitor, it's even harder to set right. And it's even more obvious that you can't grade them, as they usually start of significantly easier than they end.
I am not aware of either a written standard (at wold / IFSC level) or a fixed course syllabus to become a route setter. As far as I am aware, it still works in the usual way for emerging sports: You start off locally, get experience, get to know relevant people, get the knack of it and have fun. Then you start setting local competitions and show your prowess, get to know more people, go national and by that time it's just a question of whether you are willing to keep up the probably huge work effort to keep setting at that level. If you do, you're name will probably pop up as chief route-setter at a world cup eventually.
Yes I am aware - that was really not helpful ;)