This is a legitimate criticism of liberalism. We do want people to be free to both express and listen to arguments for and against the truth or goodness of all and any ideas and belief systems. We recognise that this process causes some ideas to become more widely accepted as true or good and others to decline in credibility or approval as a result of people evaluating and comparing them. This is the liberal concept known as the Marketplace of Ideas, and it is a feature, not a bug.