Don't take this as Pokemaster's official answer, but I'd like to give my take on this.
Giving mods access to editing the pages of this site would include giving them access to the source code of this site in some way. The pages on this site aren't edited the same way as these Pokebase posts are, but use HTML instead of Markdown.
And if Pokemaster gave them access to editing HTML, then a number of security issues like XSS and CSRF vulnerabilites arise. Mods could sneak in their own JavaScript code and compromise user data or make users do unwanted things, just by a user visiting the page with malicious JavaScript code in it. I don't want to get too technical, but if something like that were to happen, let's just say it wouldn't be pretty.
You could do things to prevent against these kinds of attacks, generally, but you can't do things like HTML-encode dangerous characters like < > " ' \ & because the site needs those for its genuine purpose, too.
A lot of the site is also most likely stored in a database and accessed server-side, and so some kind of edit-system would need to be implemented, and it'd need to be safe from security issues like the ones mentioned and maybe SQL injection (I'm no expert on SQLi so I don't know if it'd be a vulnerability here, but maybe).
I just think it sounds like a lot of work to implement if it were to be safe (time Pokemaster could use to correct mistakes on the site himself :P). And even then, it probably won't be 100% safe anyway with this kind of direct-edit access to the site because of filter-evasion techniques and the like.
It may not be impossible to implement some kind of user-submitted change system, like if you did something like GitHub (probably closed-source in that case) or if Pokemaster could review changes in some way, but I don't know what he'd think about that. I can't say, I guess.
I'm not saying the mods shouldn't be trusted though, it's not that, but it's just that this kind of thing is generally dangerous to do.