It's a sad fact in MMO's that people will take items for small benefits to themselves I have seen items taken that were going to be used for that persons retainer and even as a glamour for a persons retainer, you will never know how much that other healer was looking for those boots and they could have been legitimately trying to farm them or they could have been spiteful because that happens too, you just have to hope the RNG is in your favour even though it feels like it never is.

Best of luck in your future drops!