But at what point of trying to further our causes do we realize that the success of our cause comes at the detriment of another cause?

I believe your cause to be mutually exclusive, which it is. By building the Hobie-only fleets, you'll be pulling boats away from EMSA regattas by splitting the fleets. We all have lower turnouts at that point.

By builing the fleet inside EMSA, you can still achieve your goal of larger fleets of Hobies; you'll still have one design fleets and starts (with 5 boats of course), but you'll have the comraderie and strength of larger regattas.

Hobie doesn't have to support the whole regatta, but they could support any given fleet inside the regatta.