A very large percentage of people believe that having a functioning government is necessary and taxation is a necessary component for this. There are no examples of large populations of humans (many millions for the definition of large) living well without government. There are lots of examples of the reverse being true. That is, finding places where large populations live quite well with a government. Correlation not implying causation and all that, one can reasonably conclude that a functioning government, and hence taxation, is a necessity for large populations to live well.
There are lots of examples of functioning governments performing badly and subjecting large populations to miserable conditions. This means that people need to be vigilant with regard to the governance. It's good for people to question the decisions their governments make and people at the fringe can provide nice counter balances to group think and a herd mentality. Calling taxation theft might be a bit too extreme though.
Overall I think your view of each individual funding themselves only what they feel deserves funding is highly impractical and ignores human nature. Specifically it ignores the free rider problem. It also ignores that such a method is highly inefficient. Government is much more efficient than the solution you posed in another post of yours.
It is nice to fantasize about being like Daniel Boone and going it alone without need for government but in a nation of 350 million people that ability does not exist for any but a very few. The go it alone mentality does not scale well to large populations and have the net effect of making us all poorer.
