Because FPTP describes the election of ondividuals in a vote. Nothing about electoral colleges. Had the US Presisdential Election been FPTP, Clinton would win on number of votes.
No.
First Past the Post describes
any system in which only a simple tally of votes determines the outcome. Its alternative is Proportional Representation.
Just as PR can take many forms, so can FPTP.
In the case of the US Presidential system delegates from each state to the Electoral College are elected on (1) FPTP and (2) All or Nothing.
The tally of delegates in the Electoral College determination is FPTP.
Your logical error (you like those) is to assume that US presidents are directly elected. They are not.