If you want to be Free Libre Open Source Software then use an OSI and FSF approved licence.
If you want to be FLOSS and protect your brand from people cloning your app, do like Mozilla and use a trademark + MPL.
If you don't want to be open source don't call it open source, it's shared source or something else.
I told him and he did not seem to consider it a big deal.
At first please define "open source".
1. Do you use this term as an alias for "The Open Source Definition" [0] as presented by the Open Source Initiative? In such case, the Grayjay project's license seems to not meet this definition.
2. Do you use it in a more general sense to mean any software whose source code is publicly available? In such case, the Grayjay project fully meets this definition.
[0] https://opensource.org/osd/
I would be very cautious to assume that the term "open source" must always and in all contexts be interpreted as having the meaning described by the definition 1.
Some people do not care about using pirated versions of Office.
Some people care very much about whether software is or isn't open source especially when it is claimed to be but isn't.
Being open source means that if FUTO goes bankrupt or is purchased or abandons GrayJay due to unprofitability or decides to pivot and become anti-user or etc. etc., then the app can be forked.
The current licences is so stupid that not only does it not allow forking, it actually does not allow using the app for it's intended purpose. This is egregious open-washing.
It's not shared source, since anyone is able to inspect the source code, not just a subset of people
Open source means OSI-approved licence and that will not change.
This is shared source or source-available, not open source.
And, obviously, thanks to your comments, the debate doesn't seem to be settled.
It's also not the only deceptive Adventisten. He also claimed that you can use it how you want the only use case they want prevent is injecting ads into their app. But that could be better solved with a trademark.