Should Christians watch, or promote, media that features violence, sex or other immoral acts? Some say no, and in recent weeks the Christian rising star of the hit Amazon series "Reacher", Alan Ritchson, has faced criticism for taking on the role.

Ever since the moving picture first entered our homes, Christians have been concerned about the content. In the UK a group of Christians led by Mary Whitehouse valiantly campaigned to make TV more wholesome from the 1960s onwards. Some of their concerns now seem quaint, such as unmarried co-habiting couples or swearing, problems that seem mild compared to what we are used to today. Whitehouse became a figure of fun in the UK, and her campaigns mostly failed. Now even the secular press acknowledges that at the very least, she got some things right.

Whitehouse, who passed away in 2001, would turn in her grave if she saw the kind of obscenity that is now freely available through the internet. The explicit content of TV series and movies is bad enough. Much worse, the internet makes horrors such as genuine 'snuff' movies – real videos of people being killed – available to anyone with a bit of tech knowledge, as well as extreme pornography that features bestiality, paedophilia, fetishes and violence.

This repulsive context makes the hit Prime Video series "Reacher" and its "good vs bad guy" morality seem almost saintly. Yes, there are sex scenes, uncommitted sexual relationships, and a lot of violence. But at least there's a sense of righting wrongs, stopping evil, and the virtues of courage, sacrifice and valour.

Still, Ritchson's decision to play Jack Reacher generated enough criticism to prompt him to respond in a YouTube video that had 1.4m views at the time of writing. "I love playing Reacher," he said in the video. "I love playing a character who creates a kind of moral ambiguity that we should struggle against, as we consider whether or not what he's doing is good all the time or morally right."

He points out that the Bible has many stories of "morally ambiguous" people, paganism, war, bloodshed and magic. He has a point. Christians accept that the dubious actions of some of the Bible's heroes are not meant to be imitated – King David's adultery, pre-conversion St Paul's murders or Joshua's warmongering, for example. We can still learn from their lives and the ups and downs of their relationship with God.

In the same way, we can watch Reacher while doubting the morality of his actions. His determination to kill all the bad guys would land him in prison in real life, yet might evoke sympathy from a public disillusioned with our creaking justice system that seems to allow many to get away with evil. What is the right thing to do when justice breaks down? How should wrongs be righted? What is our own responsibility and where should we draw the line? They're important questions. Reacher's gung-ho vigilantism is one answer.

The difference with Biblical stories is that God is the central character, and the lead role is One with the perfect behaviour and morality: Jesus Christ. This provides a framework that makes it clear that the violence and bad behaviour in Scripture is wrong.

Mainstream media does not have this, so shows like Reacher can't teach us much on their own. Maybe Ritchson senses this, and it is why he regularly posts reflections on the Bible and faith on his YouTube channel Instachurch? He says his high profile role is a way he can encourage people to have faith.

"God has built a platform because of this show," he said in the video. Concerns about whether we should act in violent TV shows are just distractions. "It's funny to me how a lot of people criticize me, supposed Christians especially criticize me, for playing Reacher as if the only TV that that should exist is seeing people silently folding their hands in the pew of a church."

He seems sincere in his faith and wanting to reach people with the Gospel. In a culture that is so hostile to Christianity, it requires the guts and courage of Reacher to speak so openly. And when watched through the right lens, Reacher can help us to consider important issues. We can't turn back the clock and ignore the fact that sex and violence are everywhere. Any voices in the media that rise above to proclaim the Gospel and the love of God are welcome.

But still, if we could change the culture, we should. When violence was first shown on TV and cinema and the Pandora's box of media obscenity had not yet been opened, there was evidence that it did affect the behaviour of its viewers, especially children.

For example, Albert Bandura's Bobo doll experiments showed that toddlers who observed an adult being violent would copy and mimic the behaviour themselves. This took place in the 1960s when today's ubiquitous screen violence did not exist. Perhaps today's children are desensitised, but that's hardly a good thing. There's plenty of evidence that the overwhelming temptations of pornography are having a bad effect on society, too.

Therefore, while we do have to live and proclaim the good news using every means at our disposal, including popular TV and media - the enormous compromise this involves should be recognised. It can be difficult to imagine a society where TV violence is not the norm, but we can hope and pray for a world where love and goodness is the priority for both individuals and the media.