If said player sacrificed good strategy and potentially multiple glory stars to achieve the single glory star from the guidepost, that's on him. Most minions is really no different than earlier guideposts which were contingent upon having the most of other stuff. Think back to game 2. The guidepost was most coins/resources. Nobody got to keep all of those either after that game, but instead were limited by capacity just the same as minions after game 10. If said player gained the guidepost glory and scored well during game 10, then he should feel quite good about it.
I think the difference in that player's mind might be that at the end of Game 2,
Spoiler (click to reveal)
players got bonus VP based on the choice made by the guidepost winner, but there was no such bonus for the Game 10 guidepost.
Of course, many of the other guideposts didn't award VP either...