In the days of Roman Empire, there were many religions. There was the standard Roman pantheon, there was emperor worship, various religions imported, and those of peoples conquered and brought into the Roman fold. The Jews belonged to the latter group as a matter of fact (Paul was a Roman citizen).
People mixed and matched religion then as people mix and match wardrobes today. If one god (or group of them) wasn't getting you what you wanted... try another or several at the same time. Sure, there were the odd-ball religions who didn't do this (the Jews for example), but if you were relatively well behaved and towed the line... that was tolerated.
Enter the Christians... who fell into that odd-ball category of NOT mixing and matching as everybody else did (inheriting that from the God of the Jews). At first, they were thought of a Jewish sect and thus enjoyed the same Roman sanctioned status of Judaism. But that would not last, in large part at the behest of the Jews of that time.
Setting aside the fact that Christians were rounded up and killed in various ways. The manner and degree of persecution ebbed and flowed within the Roman Empire over time. Roman society sought to dissuade people from practicing their Christian faith and one such means was to prevent Christians from being able to work and make a living for themselves and their families; to prevent them from being able to enjoy the normal benefits of society.
Examples include the following. 1) Trade unions would adopt a patron god. To work you had to belong to that union. To belong to that union, you had to pay homage to their god. 2) Government officials required citizens to make a token (religious) offering to Caesar; failure to do that ostracized the offending denizen to the point that it limited their ability to work, buy, sell, and function in society.
"There is nothing new under the sun". Man's nature does not change. Two-thousand years later the pagan and secular world still seeks to limit faith and still uses the same means to do so.
Today, one must participate in secular and government sanctioned social norms OR lose your business, lose your right to work, face bankruptcy, face harassment by a horde of government bureaucrats, not to mention leftist activists... OR simply act against one's faith.
Of course, the main issue today affecting such persecution is the gay rights agenda. One must not only accept, but embrace homosexuality (and the offshoots or the expanding acronym) as normal and socially valuable or face the state enforced wrath of the left. Photographers, bakers, florists, etc... must submit or never work their trade again.
Like the Romans the secular left asks "What's the big deal. What is a little incense burned to Caesar, a nod to a pagan idol, participating and giving affirmation to sin?"
To Christians then and today. It's Everything... the difference between "life" and "death". The secular left will never get that, because…
“When Man ceases to worship God, he does not worship nothing but worships everything.” – G.K. Chesterton
In secular society, anything and everything can be moral and right and those who disagree will be forced to submit and worship anything and everything… IF they want to work… IF they want to feed their family… IF they want to buy and sell… IF they want to have a place is civilized society…
To all you Christians out there… it’s going to get worse, much worse.