Private server mods spam - is it necessary?

[Wahazar]

There are many custom mods created fro specific server, usually some recipe tweaks - not sure why such mods are uploaded, cluttering on Mod DB page, while they can works on server side, no need to be download by client.

Is it due to negligence of authors or maybe server hosting policy?

[QueerCoded]

I think its probably due to a combination of people not knowing how to make a mod server side only and not knowing recipes can be server side only