This isn’t uncommon at all when dealing with development that requires interoperability.

Far from it, actually.

If a part of your user base uses another service, you’ll inevitably have to add workarounds specifically to cater to users for that service. It’s just a fact of life when multiple groups have to implement a spec. If you aren’t willing to add workarounds, users will think your software is broken when they should be blaming someone else.

For example, Firefox maintains a few workarounds for websites that ship in the browser. They aren’t the web developers responsible for the sites but someone has to make it work.

Interoperability is not free.

Not free, but worth it for messaging to solve the real pain points that iMessage and Google Messages users deal with while trying to communicate across the aisle.

You're free to make value judgments, but for a business to follow through, the economics of it must be sensible. As a consumer, I prefer a secure messaging platform over an open one any day of the week.