Government workers don't cost anything. They are all "overhead." It's not like, if they weren't pursuing Manafort, they could have been doing something productive. They never do anything productive.
The U.S. is one of the few civilized countries that allows its citizens to calculate and pay their own taxes. In most countries, the main source of revenue is taxes that are collected automatically, so that no one has the opportunity to cheat. (The biggest single problem in Greece, causing the government to go bankrupt, was that most of the people with high incomes evaded their taxes).
The IRS oversees the tax processes, and ensures that the people who are required by law to pay taxes do so.
I look at the IRS as my ally, not my enemy. I pay my taxes and want everyone else to do likewise. If you look on the IRS as your enemy, then you are likely a tax cheat, and you'll get no support or sympathy from me. They do go overboard sometimes, but usually their actions are triggered by cheating of one kind or another.
