Do you really have no clue?
I'm sure that if you asked 50 protesters, you would get a wide variety of responses.
I would say the following list would cover some of them:
Planned Parenthood
It's not my place to fund that type of organization. They want it let them pay for it themselves
Pro Choice
Valid concern but RvsW probably not going anywhere
Environmental concerns
Difference in conservative view and liberal. Too bad.
Comments on women
how do you protest something that is not policy or that happened in the past
Comments about Muslims
If wanting to make sure that the radical portion of their religion doesn't get in to the US then is bad then not sure what to tell you. Where are these folks protesting when the radicals have one of their attacks
Comments about Mexicans
See comments on women
Supreme court appointees
Too bad, a conservative won. He's going to appoint a SCOTUS that fits his ideology
Russian involvement
Were they protesting Hillary's involvement with the Arabs
Education concerns
Did the protest when Obama's educational follies that last eight years
The overall nasty tone of his campaign
Would they have had a protest if Hillary had won? She was just as nasty. Unfortunately that is the norm for a presidential election
Making fun of the handicapped
It was despicable but I don't know what protesting would accomplish
The radical side of his supporters
They really showed them. Who came off as being radical?
The alt right concerns
Fears of increased racism
LOL, the old race card.
Non-inclusion
Another phantom issue
Concerns he will only answer to rich white men
Running the old rich white guys to Mexico and China has been a successful strategy in the past
The way he treated Hillary
Did they protest the way Hillary treated him? It was an ugly campaign on both sides. Unfortunately it's American politics
The lies he seems to be telling
Were they protesting Hillary's lies too? WHat about when Bill was in office?
Gun laws
Which criminals are following the gun laws?
An outlet to show their disgust and embarrassment
Based on many of their behavior including many of the celebrity speakers, who should be embarrassed?
Dang, I should have pretested the last eight years. I was extremely embarrassed as well!
To send a message to the world that many in America are outraged
Maybe I should have protested the last eight years. I was outraged too.
To show their belief that the country is better than this
Better than what? Just because he stands for something different than them? It happens every time we elect a new president. There are winners and there are losers. Try again in four years. Suck it up like conservatives have for the last 8 years.