I don't see why not. Age restrictions on voting mean very little today among the highly uneducated masses. Furthermore, seventeen year olds can work and pay taxes just like adults. I think the age requirement for voting should be the same as the age at which somebody can drop out of high school. Thus we have a baseline for the lowest-common-denominator of voting persons.

What's next the drinking age in America  will be reduced down to 17 or 18?
IMO 21 should be the legal voting age, people under that age really do not care enough to vote. During the 1970s the voting age was dropped from 21 to 18. 

they only allow 17 year olds to vote in the primaries if they will be 18 before the actual election. So the voting age is still 18 esentially.

Most 17 year olds will be tried as an adult in a murder case anyway. As for smoking age, seventeen year olds should be restricted from purchasing cigarettes because they tend to still be in school and can provide them to other, much younger and developing students. Meanwhile many 18 year olds are out of school. It's the same logic as having an alcohol drinking age of 21, despite 18 being the age of majority. Nevertheless I wouldn't mind a repealment of smoking laws, determined by the different states of course. The age of voting should be the same as the age of income taxation. If minors can work at sixteen and are taxed, then they should be able to vote. For federal voting it would be determined by the upper limit of state working ages. Which I do believe is sixteen, if I recall correctly. 

That will never happen because 18-22 are the college years and they are the most politically active age group. No taxation without representation, please. 

I'll allow it if liberals quit brainwashing kids at school.

I think this would actually act as a means to combat the brainwashing. The intelligent college-bound kids will start questioning things early on (because they've been given a duty to vote) before their college professors (who are far more competent at brainwashing than high school teachers) can do the worst. Furthermore, I've noticed a larger variety of political beliefs in high school teachers than professors, which depends much on the region of the high school. There's more accountability in the high school system than in the college education system, albeit at the expense of choice. 

I can see people wanted to push back voting age, but certainly not lowering....

TV, radio and other forms of media do a much better jobs at brainwashing, spreading propaganda convincing uneducated people that the Republicans are all good and the Democrats are all bad.

Except for the obvious liberal and progressive media bias, of course. ;) Republicans are seen as evangelicist backwards racist country folk by the media while Democrats are seen as caring, egalitarians who just want what's best for the "greater good."