RMT is not the only issue at play in this discussion.
GDKP is largely a way to make PUGs viable and attractive and the devs want community to be a bigger part of the experience in SOD. They want you to make friends and play with them rather than just grouping up with randos in a GDKP run.
If you look at the justification they gave when announcing this policy, they made that very clear.
You don’t have to agree with them on that point to understand that they at least had reasons other than RMT in mind when they decided on this.