I totally get where you're coming from, and from the perspective of "I'm busting my gut so that these people can loaf about reading books" it makes a lot of sense.
The other perspective is "I'd prefer to live in a society where people feel comfortable taking time out to educate themselves and contribute to human knowledge". We live in a social contract whereby the state funds people in higher education. It feeds into both practical research and aids the higher goal of progressing knowledge. Maybe these things aren't very important to you, but I think enough people find them important (or not enough find them distasteful) that this is the way things have evolved to be.
Besides, what actual fraction of your tax is going towards PhD students specifically? would be interesting to know the average figure.
There are limits to what the state can and should fund individuals which chose this path. Those choosing to take time out to educate themselves and contribute to human knowledge should consider those limits and their own person financial situation when choosing a graduate program. Those now striking could have chosen to pursue their studies at a school where the cost of living was lower and the combination of state contributed funds and their own personal finances were a better match.
There are limits of course, but I wouldn't have thought you're getting near to them yet when it comes to graduate funding in a strong economy like the US. In the UK it's common for graduate stipends at London universities to be significantly higher to take the cost of living into account. Even the minimum wage is higher for jobs in London.
The other perspective is "I'd prefer to live in a society where people feel comfortable taking time out to educate themselves and contribute to human knowledge". We live in a social contract whereby the state funds people in higher education. It feeds into both practical research and aids the higher goal of progressing knowledge. Maybe these things aren't very important to you, but I think enough people find them important (or not enough find them distasteful) that this is the way things have evolved to be.
Besides, what actual fraction of your tax is going towards PhD students specifically? would be interesting to know the average figure.