If one finds the President-elect reprehensible, is that a legitimate reason to not attend the inauguration?

If one finds the President-elect reprehensible, that is a legitimate reason to not attend the inauguration, unless the one is white or Republican and the reprehensible President-elect is a minority or democrat.
In such case not attending the inauguration is reprehensible or racist.

Yes. Why not? In fact, I believe that in an egregious case such as Trump, responsible citizens should participate in protests.

Hillary Clinton was not aided by Russia -- on the contrary. Hillary Clinton won more votes than Trump.

It is difficult to imagine the two situations turned around, but even if Hillary Clinton had won the electoral college votes but lost the popular vote, at least she would have done it without Russia's interference.

Of course.

Just because he managed to fool a sizeable proportion of the public, and roused the worst instincts of the other, doesn't make him any less unfit for the presidency.

In good conscience, you could not attend his inauguration if you saw him as unfit for office.

Mowing your lawn or painting the bathroom are "legitimate reasons" to not attend the inauguration, if you needed one. People saying they are skipping it, are just making a political statement, like the boycotters. Me, I have never watched an inauguration, even when my candidate won.

I do find him as such. But that will not be the reason for my absence.

Nor, your belief in the system and respect for the office should be more important than your feelings about the person.

No law requiring anyone to come.

Last thing we need is a bunch of malcontent sore losers ( or just losers) taking up space.

Notice how Hilery thugs were more than happy to attend Trump rallies the last 6 months. (to start fights)

why do you need a reason, legitimate or otherwise, to not attend the inauguration?

I won't be attending, either.

Why do you think you need a legitimate reason to not attend. Simply don't go.

Sure. What's not legitimate is presenting a legal case and going on national news to tell people about it. That's defamation.

If someone is defending them self, that's not defamation because it's all in how each context was created.