Because everybody else did, including Timothy McVeigh.
Some quotes:
"McVeigh was reprimanded by the military for purchasing a "White Power" T-shirt at a Ku Klux Klan protest"
"he spoke daily to his co-worker Carl Lebron, Jr. about his loathing for government. Deciding that the Buffalo area was too liberal, he left his job and began driving around the country, seeking out his old friends from the Army."
A letter he wrote to a newspaper:
"Taxes are a joke. Regardless of what a political candidate "promises," they will increase. More taxes are always the answer to government mismanagement. They mess up. We suffer. Taxes are reaching cataclysmic levels, with no slowdown in sight. [...] Is a Civil War Imminent? Do we have to shed blood to reform the current system? I hope it doesn't come to that. But it might."
"McVeigh introduced his sister to anti-government literature"
"For the five months following the Waco siege, McVeigh worked at gun shows and handed out free cards printed up with Lon Horiuchi's name and address, "in the hope that somebody in the Patriot movement would assassinate the sharpshooter." (Note "Patriot movement" was the way right wing extremist groups were re-branded in the 90s, just as alt-right and some other names have been used since.)
He made his meager living selling copies of The Turner Diaries (a novel that fantasizes about an armed revolution against the US government, and genocide of blacks, Jews, and gays: https://en.wikipedia.org/wiki/The_Turner_Diaries) among other right wing literature at gun shows.
I don't see how he can be considered anything but right wing, and pretty extreme right wing, at that.
Source for all of the above: https://en.wikipedia.org/wiki/Timothy_McVeigh