I have encountered this too. I don't force people to use Signal, but I also don't use any other messenger, so if they want to contact me they will just have the use it and else the content is probably just not that important.
TPB AFK: The Pirate Bay Away From Keyboard is a 2013 Swedish documentary film directed and produced by Simon Klose. It focuses on the lives of the three founders of The Pirate Bay – Peter Sunde, Fredrik Neij, and Gottfrid Svartholm – and the Pirate Bay trial.
I have encountered this too. I don't force people to use Signal, but I also don't use any other messenger, so if they want to contact me they will just have the use it and else the content is probably just not that important.