I don't think it's necessarily a moot point. To the extent government extortion revenue gets diverted back to projects which actually serve the public, we must be good stewards of that money. And since our budget is entirely disconnected from the taxed individuals thanks to the fungible nature of money, we need to strive to ensure the entire community is served to the best of our abilities.
Of course the idea solution might look like a membership subscription answerable to the members directly, or a charitable trust fund functioning as a neutral service to all. Some libraries in the US are funded by these methods instead of property taxes. Homeschool associations and churches often set up libraries for their members informally, too. But while this is possible, the real hurdle is persuading people that it is the proper solution. In the mean time, getting mad about library books is a waste of effort when far greater injustices exist.