Take the London marathon for example. Anyone can take part, but only a few people are allowed to start at the front. Runners must achieve a certain time at other accredited marathons to be able to start at the front. Those who do are classed as Elite level runners.
So I don't see it as a boastful thing, just a matter of fact. If thewizardofaus has reached this status in their sport, then it's reasonable to use the term when describing themselves.
In most sports, there isn't really a formal distinction between elite or competitive or whatever. Professional just means paid, elite or not (lots of golf pros would not be elite by most people's definition).
Anyways, in my little corner of athletics (local 5k-10k running, mountain biking), if a promotor has an "elite" category, it's usually just the name for the fastest wave of athletes. They probably get a front-row start, at a marathon they might have their own hydration/nutrition at aid stations, and they may or may not receive an appearance fee. Local running clubs (competitive ones) tend to have "elite" divisions, where athletes must qualify by pace/results, and this gets them club-funded event entries and possibly travel expenses. In mountain biking, at least outside the realm of international sanctioning bodies, the fastest category is often labelled "expert/elite" or similar and athletes self-select into it (vs sport/intermediate, beginner, masters 45+, or other categories).
i am confused too. i am genuinely curious about this label
Professional means getting paid to do something.
Not all elite athletes are professional athletes, and not all professional athletes are elite athletes.
For instance, major running events typically have an “elite” start vs the mass start for non-elites. And elite is the exact word used.