Working for something and it being a subsidy are not mutually exclusive. Indeed, I think it is usually the case. Farmers are often subsidized - no-one would argue that farmers aren't
working. Miners do work and provide a service. Ideally we want them to be paid entirely out of transaction fees, but we subsidize this work through inflation until that is possible.
I agree this inflation is a tax on holders, but when it is paid out, it is something else - call it a subsidy, reward, allowance, grant. Subsidy i think is most technically accurate,
It may be most often called a subsidy by holders who don't mine, but I could be wrong. I think they might do that to displace the thought of paying a tax at that particular time.