That's literally NOT the purpose of the tax system. We tax people to pay for government expenses. Encouraging/discouraging behavior through taxes is very popular in the US, but not nearly as much in most other countries.
It depends on the level of government and their sovereignty. If the government controls it's own currency, the purpose of taxes is not to pay for expenses, but to provision the government, create a demand for that currency, and create markets. Sovereign governments are in a perpetual state of deficit on purpose.
Governments in the Eurozone are not Sovereign because they don't have control over the currency and must use taxes to pay government expenses.
US states and cities also must use taxes to pay for government expenses.
So the real answer is complex, it depends on whether you are a sovereign government or not.
True, but America's history means that it has a relatively weak and slow federal government. Tax initiatives are some of the fastest things one can pass on the federal level.
Depends on the level of government. For cities and states, taxes generate revenue, but for the federal government, taxes serve a different purpose because the US federal government is sovereign and controls it's currency.
This following is an excellent short video from the late David Graeber explaining why money is debt and what taxes do. While it's context is the UK, it applies to US or any sovereign government.
For California it's absolutely about revenue. But a dual purpose is to provide incentives/disincentives for certain behaviors. Even states that require taxes for revenue give tax breaks for incentivizing certain things to companies and other groups.
At the federal level taxes serve to mainly provide a demand for the currency, control the levels of money in the broader economy, and incentivize/disincentivize behavior. Unlike cities and states, the federal government must necessarily be in a perpetual state of deficit for the private sector to have a surplus.
To further back up Gaeber's claims, here is a reference from the Bank of England explaining how money is created.
