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 - - health dept has provided free birth control for decades
Pro Choice --- roe v wade standing strong since 1973's decision
Environmental concerns ---- Obama's record wasn't that great towards Mother Nature
Comments on women --- sticks and stones...
Comments about Muslims --- vetting of future terrorists, do you let just anybody come into your home
Comments about Mexicans --- some illegals actually are criminals, imagine that.. sur13 Gangbanging
Supreme court appointees --- can they name anyone on his list, do they know he has a list
Russian involvement --- unproven... Clinton's election rigging is proven
Education concerns --- education systems sucks due to common core
The overall nasty tone of his campaign --- basket of deplorables
Making fun of the handicapped --- Hillary has ridiculed disabled and homeless
The radical side of his supporters --- see recent riots from the Dems
The alt right concerns -- alt left concerns
Fears of increased racism --- they can thank Obama for the worst racial tensions since the 1960's
Non-inclusion --- see fly over states
Concerns he will only answer to rich white men - but they said middle class rednecks elected him
The way he treated Hillary --- would they stroke out to know they are friends...lol
The lies he seems to be telling -- it was 30k + recipes and yoga moves
Gun laws --- are just fine if they were enforced in a consistent manner...but guns are so big and scary right
An outlet to show their disgust and embarrassment --- other side used the voting booth to show their disgust
To send a message to the world that many in America are outraged --- see above and voting booths
To show their belief that the country is better than this--- Madonna and Ashley Judd are such role models