Well thats just wrong, thats what /srv/http is for, to serve http, but historically websites were served from your home, as then they where known as home (personal) sites, and they're still known as "home sites" in many non-english languages.
Now when you have web applications they can be in /srv as well and the database is usually wrongly put in /var (looking at you mysql) but what you gonna do when you need a system user, just like a users stuff is supposed to be in home so put your database there /home/postgresql/its_datas here, as anyway you need to run the db as its own user.
One would certainly never dream of keeping entire web sites in there!