I know I cannot win this one, but on my last attempt to reason with them, I asked for a list of allowed domains...
ritchie
You practically either have the option to use your "subdomain" e.g. foo@mylittlepony.addy.io or if you are fine with random characters, then you can have an address on the main domain e.g. xhgj18273@addy.io. Unfortunately this is not the first provider I see only accepting big tech addresses/accounts...
The idea is that is it more "real" than the other social media apps, because you cannot prepare your best self for the photo and not necessarily the best memory of that day will be recorded. Reality is that most people (maybe all people) have a relatively boring life (it's not everyday that something worthy of attention happens) and there is not much value in sharing e.g. your lunch. Most people had it that day and yours was also not that extraordinary.
Unfortunately since facebook (maybe instagram topped it) everyone may have their own tabloid platform to share their everyday life as celebrities do on tabloids and people seem to love it.
Not to mention the huge privacy concern that you post of a photo everyday, which may include your location, definitely your face and other useful information that may be used to hurt or annoy you in some way.
I have a laptop that needs a proprietary wifi driver. I just "love" it when the debian net installer works out of the box, but after first boot wifi dies because the driver is missing in the installed instance :D I need to find a lan cable, do some athletics to get to the router, then install the driver and only then I can connect via wifi :D
Most probably true. It is sad though that they are not straightforward about it so that they send a list of domains they like.