No, I don’t think so, and I also don’t think that everyone who disagrees with you is being dishonest. That’s why ideological viewpoints like yours are so misleading.
1. Australians are a tiny minority in America. Most people have never met someone from Australia. Whether they are stigmatized or not is frankly irrelevant. They play almost zero cultural role in American English.
2. Having different pronunciations by default makes it not standard American English. Not sure why this is controversial. If 90% of the country uses a certain pronunciation, why is the 10% one just as valid? Is the avoidance of it discrimination? I don’t think so. More like basic practicality.
3. Again, you seem lost in a loop here. Either AAVE is a separate dialect with its own internal grammar, or it’s an extension of Standard English that uses incorrect grammar. Which is it?
4. Considering that pretty much every other dialect is treated exactly the same way (Appalachian, etc.) it’s pretty clear this has little to do with race, as you are ideologically trying to shoehorn into your argument.
You see some grand conspiracy when the reality is that standard American English has a longer history, more cultural works, and is agreed upon by the majority of the population. It’s really that simple.