This recent photo of Trump reminded me

[coti]

36. No, there is only one Boxer character. "Boxers" would imply more than one separate entity

originally named Boxer- more than one actual character named "Boxer." For example, "Boxers" would mean, in the event there are two (as opposed to more), there is a horse character named Boxer that's brown, and another, totally separate horse character named Boxer that's black. That's two "Boxers," which isn't what the writer meant at all. Thus the apostrophe, to attempt to imply the singular character.

Another example where it would be appropriate to use such a proper noun without an apostrophe is where there is, indeed, more than one entity referred to by the proper noun. For example, the sentence: "All them Trumps is cheats, chiselers and swindlers." In that sentence, there are many separate entities who fall under the proper "Trump" category, thus it is right to just thrown on the "s" at the end of the word.

The examples you gave uphold this distinction.