Bitcoins are limited and demand for them is continually growing due to privacy concerns, tax avoidance, media attention etc. Bitcoin being limited is what makes it deflationary unlike fiat currencies.
Although i agree tha bitcoins nature is deflationary, you just mentioned all the wrong reasons about why bitcoin growths. Tax avoidance, privacy etc it was some of the dreams of some libertarians that initially endorsed the currency. Since then much have changed. Just see how the price has skyrocketed after the closing of SR.