Call Allah Instead Of Khuda
There’s no reason to insist on anything. It’s a matter of personal preference – as long as there’s nothing inherently wrong in the name we should not restrict people. As you stated earlier, even Allah was a common name amongst the audience of prophet Muhammad SAW. He did not invent a new name because there wasn’t anything inherently wrong with it. In Arab countries people of other belief systems still refer to God as Allah. It’s an Arabic word without any significance particular to Islam.