While I'm not necessarily unsympathetic to your plight, I'm a bit worried about any implementation.
It'd be very difficult to create a way in which readers could easily read a chapter without aggregators getting to it as well.
[ul]
[li]You could restrict certain manga to registered users only, but that would simply require bots to make and use an account.[/li]
[li]You could require passwords, but that is retrieved automatically fairly easily too, as long as you post it in a place readers could easily find it[/li]
[li]If groups not just post their scans on mangadex but also choose to share them on their personal blogs/sites, as many do, aggregators would just retrieve chapters from there instead[/li]
[/ul]
It's the DRM issue. Every bit of friction you add is more easily overcome by tech-savy people and bots than users; the latter of which will at a certain point just turn to said aggregators because it's less of a hassle.
The best compromise would be CAPTCHAs but those aren't foolproof either, and people still hate them.
(Also: too many phede's here, are you related in any way or just very like-minded?)