Trying to understand the rationale here. So Iran are blocking WhatsApp and other messaging services by blacklisting IPs or filtering the traffic? Is the idea that people will connect to random proxy nodes for signal that will circumvent this blocking?

Edit: as a follow up question. Do the people of Iran need messaging access to people outside of Iran or more likely their friends and family within Iran. Most of these messaging services are centralised so blocking them means cutting off communication within the country as well. Maybe they'd benefit from running private messaging servers themselves?