Yesterday I had to remove the standard female header pins on an Arduino Due to replace them with male headers. Desoldering long pins or double-header pins is not hard if you follow the trick mentioned in the video. Remove the plastic housing to reveal individual pins to divide and conquer each pin. Use a strong tweezer else you will bend the edge and ruin the tweezer. I always have a separate tweezer for mechanical work so that it doesn’t ruin the fine tip of the tweezers which I use to pick up electronic components.
Apply flux and the important thing here is to add a good layer of leaded solder(Which contains lead). Leaded solder has a lower melting point and really helps in heat transfer. It makes sense to use it for desoldering as most professionally made boards these days are RoHS compliant and use non-leaded solder(which has a higher melting temp). So in order to avoid overheating the board, a blob of leaded solder will make your job easy.
Run the hot solder blob over the pins to easily pull the pins one by one.