This is a question that I have been asked directly on more than one occasion. Whether or not you have been asked it yourself, I think the odds are good that you have at least heard or seen it asked somewhere. I think one of the main reasons why many people see such a contradiction (and thus hypocrisy) in Christians who say they support religious tolerance while also continuing to witness to non-believers is because of a fundamental misunderstanding of what we mean by religious tolerance.
Now I have to admit that religious tolerance surely means different things to different people, but for me at least it has never been incompatible with evangelizing. I think that people of all religious traditions should have the freedom to pursue their beliefs as they see fit (probably excluding human sacrifices and such, though a religion sacrificing its converts might soon find itself with none left). That is the core of religious tolerance; freedom. It is about being willing to listen to other beliefs even though you may disagree. It doesn’t require you to believe that all religions are equally true, nor does it even prevent you from criticizing the actions of certain religious groups. In fact the statement of Christians (or any group for that matter) that our beliefs are correct while contrary belief systems are incorrect doesn’t in itself constitute intolerance.
To give you a (poorly constructed) analogy, imagine you play trumpet and your friend plays clarinet. You believe that trumpets are clearly superior, and attempt at length to convince your friend of the merits of trumpets so that he’ll give up his clarinet and join you. Now whether your friend does or doesn’t choose to go buy a trumpet doesn’t mean that clarinet playing should be banned and trumpets forcibly made the only instrument.
In the past I have also heard Christians called intolerant particularly for their beliefs (and outspokenness) about the behaviors of others. This especially crops up when discussing issues such as abortion or homosexuality. Unfortunately, I think many Christians can go too far with their words and actions, but this doesn’t mean that simply the act of speaking out about the actions of others makes you intolerant. This is true for the same reasons Christians can believe their religious views are correct and others are not without being intolerant. Tolerance doesn’t require you to accept every different idea out there, merely that you be willing to listen. In a somewhat ironic twist, it’s been my experience at least that those who yell loudest about Christian intolerance are being just as intolerant as the people they decry.
Strangely though, I have also heard some people say that religious intolerance is a good thing, that Christians should in no way tolerate false religions or gods, that the Bible itself teaches religious intolerance. I think I can at least understand where someone might be coming from who held this view, but I think they also have largely misinterpreted the message. We shouldn’t force Christianity upon anyone; they should come to it of their own volition. When people attempt to do this, through physical violence or written law, it does much more harm than good. It gives Christians everywhere a bad name, and degrades the reputation of Christianity itself. And how do we know that those ‘converts’ are truly Christians? If someone forces you to choose something, can you honestly say you had a choice at all? Christ told us to go and make disciples of all nations, but he also gave us free will. And if God gave us something, who is man to take it away?