While you may get relationship points with Josy for following her, and no points with Maya for following Maya, the game also keeps track of who you choose to follow (and who you told Derek you were still interested in).
Those flags will likely be relevant later , much more so than the RPs you received (or didn't receive) from your choice. However the RP distribution at this point only provides points to Josy because she is way behind Maya's tally at this time in the game (because she's been out of the game for so long and the scoreboard needs to be leveled).
So don't consider there to be no reward going with Maya, if you want to chose Maya, choose Maya (but seriously, who would choose Maya over Josy anyway?)
Don't get confused about the nature of relationship points. It's rare (so far) that the relationship points have been used for anything in the logic. It's typically subtle things that are changed if the relationship points are above an arbitrary threshold, but notice that the choice of the throuple had nothing to do with relationship points and everything to do with previous actions, same as the Jill shower scene. The same goes for most major branches, it's about actions and affinity, not relationship points.
Mostly the RPs are there to give a gauge as to how the relationship is going ("non existent", "lukewarn", "friendly", "very friendly", "something special" - those gauges are made up by me to illustrate the point, the game actually uses unique descriptions for each character in the end of each episode based on the relationship points and what happened in the episode).
Just to give you a further indication as to how unimportant relationship points are, the following are the only times where they are used for each character:
Bella
Jill
Josy
Maya
Sage
