Historically, the Jewish people have faced the most persecution. They have been horribly mistreated and slaughtered so far back into history that it's referenced a multitude of times in the Bible.
In the modern-day, it is Christianity. Certainly not so much in first-world countries such as the United States. However, Christianity has been rated as the most persecuted religion in the world for the last few years at least. According to a research report by Rupert Short, "200 million Christians (10 percent of the global total) are socially disadvantaged, harassed or actively oppressed for their beliefs."
Furthermore, between half and two-thirds of Christians in the Middle East have departed or been killed over the past century. Between 1990 and 2013, Iraq's Christian population plummeted from 1.2 million to fewer than 200,000. It is estimated that 7,100 Christians died for their faith in Indonesia in 2015. 78 Christians in Pakistan were killed via bombing in 2013.
According to the Pew Research Centre Report, Christians faced persecution and/or harassment in no fewer than 151 countries.
Christianity is heavily persecuted today. Just because it does not happen frequently in first world countries does not mean it is not occurring.
There are several countries where being a Christian is punishable by imprisonment, torture, beatings, and death. And I am not just talking about North Korea and China. Just Google "Christian Persecution Map". It's not in the US, but it is real. People die for being a Christian all over the world.
In Asia (esp. China, Russia, other communist countries, and the Middle East) Christians are persecuted and slaughtered by the thousands. The Islamic Terrorists and the Extreme Communists do far worse to the Christians than anyone has ever done to the Islamic people or the Jews. Hitler had nothing on the Chinese and ISIS.
Liberals have attacked all Christian values as outdated and bigoted and villainized anyone who disagrees with them especially Christians. Christians in muslim countries are being slaughtered but there is little mention of that in the media. Christians in America are denied religious freedom. Attacks on Christian values are mainstream and all over primetime, all while they try to enforce "tolerance" for everyone else.
As far as I know... Christians haven't received a mass genocide in the past century. Neither are they being banned from entire countries on the basis of their religion.
Most of the criticism toward Christianity is that they're trying to enforce their religious beliefs over everyone else. For instance, the Republican Party. I find that perfectly fair and reasonable.
Christians are attacking our liberal values and everything Liberalism stands for. For example often Christians are against homosexuality and LGBT community in general (https://i.Ytimg.Com/vi/Nmekb4k-ZeM/hqdefault.Jpg), many are against Atheism and are stupid enough to try to convince other that God does exist without any real Evidence (https://www.Youtube.Com/watch?V=DqkZToHL57U&list=PLA4AD71E546A83D85) and very few Christians are open mined people.
Personally I have never had anyone insult me because of my religion and don't know anyone who has been. As for religious freedom, it affects more than just Christians. I would also like to say that baking a cake for a gay wedding probably isn't that bad. Christians also have had way more influence in the U.S. than any other religion. The world is not out to get us.