The issue with such a statement is that the terms can and do mean different things to different people. I probably have a similar definition of computer and app

The issue with such a statement is that the terms can and do mean different things to different people. I probably have a similar definition of computer and application as you, but many people, maybe the majority, may not. For one thing they might think of a phone as a fundamentally different thing from a 'computer' with a different role. In fact I strongly suspect this is the majority view. Within that people probably think of an 'application' as fundamentally a pre-screened, pre-approved, piece of software to enable some function specifically on the phone and within the phone's ecosystem. Not as any arbitrary piece of software. In fact that might all be seen as a feature, not a limitation, in the majority of people's eyes. Again I strongly suspect that is the case.