Looking through much of this thread, I can see that many people don't understand the point.
The only relevant arguments against the OP are that a) nobody is avoiding buying 5e due to their feelings about Hasbro, and b) supporting any kind of 5e supports the whole ecosystem of 5e, and therefore, supports Hasbro. Both these arguments contradict each other but should still be addressed separately.
There have been enough comments on this thread to show that, yes, people are avoiding all things 5e - Hasbro or otherwise - due to Hasbro's actions. That suggests that the OP does have a relevant argument.
As for the second argument, I see some validity in it. If I buy a 5e adventure to run, even if it is published by Kobold Press, my players are more likely to buy a D&D Player's Handbook or use D&D Beyond. However, refusing to buy anything 5e-related is more likely to hurt those independent publishers of 5e materials, including EN Publishing and Kobold Press, than Hasbro. If someone were upset with WotC/Hasbro about the whole OGL fiasco because the company's actions would hurt independent 5e publishers, why would such a person then take another stance that would also hurt independent 5e publishers?
Level Up 5e is not D&D. Tales of the Valiant is not D&D. Even 5e adventures and settings published by independent publishers are not D&D because players have a plethora of 5e systems to choose from. Supporting independent publishers likely has a negligible effect on Hasbro's bottom line. By refusing to buy all 5e products, regardless of publisher, you are hurting the very people the consumers were trying to protect during the OGL fiasco. Refusing to buy 5e at all was never the goal.