First of all, some merit sources are there. They are just not publicly known.
Most of the MS are publicly known, and the reason is very simple - the number of merits that such members give is generally much higher than the sMerits they get outside the merits source (forum). Look at the bold members
here. How do you know, if someone is selected or not? Not all merit sources are public. And also: becoming a merit source could also mean, that person would have less merits to distribute, not more (for example: if I would be selected, I would probably lose some merits, because of that).
~snip~
The easiest way to find out that someone has been selected is for him to publicly admit it in the topic he opened for this purpose of applying for the merits source. It is not something that makes sense to hide from others, especially those who have publicly expressed their support.
If I understood you correctly, you seem to think that you can lose merits (what is visible in your profile) if you give too many merits to others? This is simply not true, the number of those merits can be reduced only by the intervention of the admin in case of abuse - the only thing that can be reduced is the number of your sMerits, which are visible only to you.