Yes, all United States citizens of voting age should be required to vote. All citizens have a duty to choose who becomes the next leader of their country. that is what makes the country's government work; active participation by the people. To make the process easier, mail-in ballots should be more readily available and a "none of the above" option should be offered.
No, nobody should be forced to vote. Especially if there isn't some they want to vote for or feel comfortable voting for. Some politicians will do anything these days to get votes. If votes were made mandatory, they would vie for them by any means possible, including telling blatant lies.
Most citizens have no idea whom they are even voting for as it is, in regards to the positions of each candidate on a variety of issues. If anything, the voting process should eliminate "straight ticket" voting, while also removing the candidate's party affiliation to avoid bias among the uninformed.
No, not all U.S. citizens should be required to vote because it is a matter of free will whether someone will vote or not. Requiring everyone to vote would be just as bad as banning certain people from the same privilege. It should be easier for everyone to vote, but it should not be mandatory.