Airplane mode is essentially a software kill switch. If it were a hardware kill switch, your workaround does not work either. What you are using appears to be a bug, and your complaint is a bug within the bug. The workaround you are using shouldn’t work in the first place.
The problem you described is not the core issue, as the expected behavior in airplane mode is that all radios are off. That you prefer to have some radios on is OK, but then you disable the radios you don’t need, and enable the ones you do need. You can add the LTE toggle in the pull down menu, to name an example.
The bugreport should be that WLAN is possible while airplane mode is on; it should not be possible at all. Whether one calls it airplane mode or offline mode does not matter, that is just semantics. Why would people expect to be able to use WLAN when their device is supposed to be offline?
That’s my opinion (IMO based on facts). You’re entitled to yours, and I am entitled to mine.