My two hockey pucks are very simply based on this
New members are cautioned to consider choosing handles that do not personally identify them and that will also be relevant as the member progresses through various stages of life.
And with that, imho, the only "exception" to changing a handle should be for correcting a spelling error as anything else is based on the previously quoted section. Yes it sounds harsh but to me it's a trivial matter for F/t staff to deal with as I'm sure there are other more important things they have to deal with. We're all big kids and have to live with decisions me make throughout all our lives (and for inquiring minds, I was almost known to you as "Slapshot" as that was the name of one of my cats at the time but i decided to change it at the last minute)