I haven't tested this in anger (ie real life situation, although anger for people quoting the OP isnt that far off....)But, if the "collapse" button is at the end, you have to scroll through the whole, horrible, quote to re-collapse it.
The "Spoiler" button sits ahead/above the content, and toggles between "show" and "hide". I thought the intent was to provide the same control over the display of a quote.
Can you make the entire quote sensitive to a tap so I don't have to scroll to the beginning or end to find the "collapse" button?
(Of course then I'll complain about not being able to mark text to copy/paste elsewhere.)
However, It is the case where people "catch me off guard" and I go to check their quote in case it has some extra info that makes their question clearer, and its usually before scrolling I can tell its the OP / irrelevant, so would wish to collapse it before I scroll.