Again, the people who are creating shouts must appeal not only to the best DD, but to the rarer support jobs. They have the right to limit who can join who can't based on whatever they want. If you don't want to level a support job to get gear:
START your own shout and you can then invite whoever you want
WAIT for a shout that doesn't care about RMED*
JOIN a static or LS that doesn't care about RMED *
or you can:
CONVINCE support players to get "paid" less per run for the same amount of work as before
CONVINCE 1/2 of player base to play support jobs or PLDs in order to equal out the amount of support to DD ratio
It will only get worse for those who just WAIT. Progressive credentalism is going to happen as they release "higher level" content. Unfortunately, the progressive credentialism is going to mainly target DDs because their is a MUCH larger amount of DD players than support players. If it was the other way around you would see shouts for "Daurdabla BRDs only", "Yagrush WHMs only", etc.
*Example: our shell did two Morimar Basalt Fields Delve runs last night. We didn't require RMED. Instead we were able to filter people on their play skill based on our past experience with them and their attitude upon joining. Out of the three shouts that were going on at the same time, ours filled the fastest. It was appealing to DDs, definitely. It was also appealing to the support jobs, since we were providing 2x BRDs, 2x WHMs, 2x PLDs, and 1x COR from the start. We still had to shout to fill the rest of the support, but they filled out pretty fast. So, these shouts do exist, but we still had to provide the majority of the support in order to make it happen.