For me it’s quite simple, Joe hasn’t played enough games and isn’t 100% back up to speed yet and Alfie isn’t quite ready yet. I know that sounds like the perfect reason to send them back last weekend to get game time but I genuinely don’t think Eddie thinks like that, in his head he thinks they will get more benefit training with England than playing for Wasps and he needs a certain amount of bodies for training. I don’t believe Eddie favours one club over another because I don’t believe he gives a toss about anybody else’s needs when it comes to rugby
That is the only reason I can think about that makes sense without going in to some conspiracy about Jones hating Wasps.
He expects Marler to play against Wales plus his well known mental health problems with travelling, but he needs game time, so sending back to his club makes sense. He knows Joe probably won't be playing, because he hasn't got enough game time, but he wants him around just in case and to help with training. Alfie's a different beast, he hasn't become an England fixture yet so either Eddie is still considering him on the bench, he wants to mold him or he wants bodies for training, maybe a bit of all three.
Jones isn't paid to consider the effect on teams and to be fair it would drive a man crazy going through all the permutations when considering the 6N rest weekend.
All this would be easier to accept if Jones was such an arrogant sod who delights in playing mind games with just about everyone, including England and club fans.