Love Island is an island of love and friendship as the name indicates. You need a pokemon that loves you to break these special rocks.
At least thats the explanation I like to go with.
Its been almost a year since the Q&A-stream where Walross mentioned he will put an NPC for that feature if it will take too long to implement it into the client itself.
So it would be nice if that feature could be introduced now via an NPC since having a Membership should never be a disadventage for the player as it can be currently.
Hey, welcome to the game and the community.
I saw you a couple times at the discord already, dont hesitate to go there if you need help or just want to chat with the community.