Many reasons for what?
FYI Trump can't do anything to stop abortions. Conservative majorities have voted in favor of abortions in the past. The current SCOTUS bench is not an exception. Brett Kavanaugh said he will not vote to change the precedents set by Connecticut vs. Casey and Roe vs. Wade, among others. Every abortion law passed in the last three years has been blocked or overturned. So his position on abortion is totally irrelevant.
Nothing could be further from the truth than saying Trump believes in the Constitution. If he did he would not have run for president. See what he was impeached for. See his comments about shooting somebody on Fifth Avenue and his power being total. See everything he said or did about punishing others for using their right to free speech or prevent them from doing so whenever it is about him being bad. Also, look at what he has been doing to prevent voters from voting by mail early enough to get their votes counted on November 3. Only people who are totally uneducated about the man could possibly think he cares one bit about the Constitutional limits on powers of the President. He only wanted the job to abuse it.
If Trump loved America, he would not call troops who died in combat "suckers" and accuse everyone who disagreed with him of being a "never Trumper" including members of Congress and the executive branch. He would not tell everyone to disobey the nation's top infectious disease experts who use research to say, "Wear a mask and social distance." He would not intentionally appoint people who think climate change is a hoax to run agencies that exist to tackle the problem, which has been proven around the world to be an environmental crisis caused at least partially by humans.
Everyone is against riots. Biden made that very clear. BLM protests start peacefully and become riots just because police want to violate their rights of free speech and assembly. What Biden wants to do is end all the racial injustice and police brutality - the problems that caused every riot to start. What will Trump do to fix those problems? Nothing. He is a white supremacist and loves the Confederacy flag.