I've seen that too, but it's usually the same people who just reject anything hosted somewhere else with statements like "we're not doing airquotes The Cloud" and think all tech companies are conspiring against us.
No, it's because all of the big chat applications are hosted in the US and this is a completely unacceptable country to have any data in.
This is true. If you are in the EU you might not even legally be able to use a US hosted solution depending on what data you are sending over the chat...