I’d say it’s unethical for any media to use the image of another company’s product without paying for it. I’ve never really understood the issue with product placement, though, as long as it’s a natural fit.
I’m not seeing how this is a good move. They’ll continue to depict the same weapons in their games, they just won’t pay for the right to do it. That doesn’t seem ethical to me to knowingly use someone else’s intellectual property or trademarks without paying them.