Why are both wires white and black hot at the outlet, and light switch and even at the light in the ceiling
In the case of a light switch, it is normal if the switch is setup as follows:
[elec ]B=========#==============+ [panel]W--------+ +X---------X+ | | | | | (~) [-] light switch
The white wire is carrying power back to the light, and convention dictates there should be a piece of black tape (X) around the white wire to indicate it is a live return.
It's important that the switch must go against the live lead not the neutral.
-- Minor edit to diagram. The wire from the panel usually ends in the ceiling. A new wire runs to the switch, black to black with a nut, and white (switched hot) back to the fixture.
# indicates this nut.
In all reality, there is no official distinction of what color wire is for what. However, common convention says the black = hot/powered/charged/incoming, white = neutral/return, green = ground/earth, and red = switched.
When it comes to 3/4 way switches, it's not uncommon to see 2 blacks, 2 whites, or each color as hot. Same for switched outlets or outlets running in parallel. If an inexperienced homeowner did any kind of rework, could also explain it.