Right away, you might think that this feature is useless/unneeded, but at least 60% of my friends wanted to or have unfriended everyone on their friends list, this would normally be used if somebody has around 100+ friends and 90% of them are not needed or they were just randomly added. It would take a very long time to unfriend 90 people one by one, and even with the feature I suggested in the topic earlier, it would still take a very long time.
Some people might not want to unfriend everyone on their friends list but they would like to unfriend most of the players, there could be some sort of whitelist that do not get affected by the Unfriend All button.
Since some people may click Unfriend All by accident, there could be a confirmation pop-up message that would ask something like…
"Are you sure you would like to unfriend all?” ”This action cannot be undone"
I think that the chances that people accidentally unfriend all their friends is too high.
I also think that some people aren’t always aware of the action and that it couldn’t be undone.
2. This function is not regularly required
I don’t think that there are many people who need to unfriend all their friends multiple times.
I would prefer a faster way like you already suggested in another topic because I think there will be too much accidentally ‘unfriend all’ action.
This feature would fit better in the Following tab, because there isn’t an amount on people which you can follow so I think that there would be more demand for a feature to clean them up on a fast way.