I'm more shocked about and curious as to why anyone would take time out of their day to press a button that does nothing other than to serve as a poor man's "read receipt" to indicate to the trolls that you read their message, thus incentivizing even more trolling.

But I assume nobody actually purposefully presses the button; only sometimes doing so by accident.

Because people’s lives have become collateral damage for performative cruelty by the current administration and its supporters.