For most people, tolerance means allowing people to believe whatever they want without fear of persecution or prosecution. This means that if I think a goat from Mars is the god of the universe, I should be able to think that and promote that without being jailed or bullied.
The real question is, does the fact that I have that belief mean my belief is just as true and valid as any other belief?
The logical answer to that is NO.
Now, before we start asking why is this view is true and not that view, let's deal with some basic laws of logic. Logic is not the stuff Mr. Spock talks about on Star Trek (in fact, much of what Spock says is not logical). Logic (from the Greek Logike), deals with valid reasoning but especially in philosophy, science and mathematics.
4 basic laws of logic are:
For example, if I say Tom is both a man and a woman, this statement cannot be true if I mean that Tom is both a gender man and a gender woman. However, if I mean Tom is a gender man but behaves like a woman, then the statement is not contradictory and does not violate The Law of Non-Contradiction.
Keeping this in mind, lets take a look at religious views. While there are many religious views, they cannot all be true. Au Contraire, you might say, all religions teach being good, loving humanity, etc. True, most religions have these basic tenets, but it's the differences that show all religions are not basically the same.
Hinduism is pantheistic - that is, they believe that God and the Universe are one in the same and that there is more of a divine consciousness that we are all a part of. Christianity, Judaism, and Islam are theistic - that is, they believe God is a unique person and is separate from His creation.
And in comparing those theistic worldviews, Judaism and Islam teach a works based or law-keeping salvation (and in Islam, being perfect is still no guarantee) as where Christianity teaches a substitutionary atonement for sin based on the Crucifixion and Resurrection of Jesus.
Here, you can see that all of these worldviews cannot be true. So, how does this translate into our pluralistic society and how we approach tolerance?
The problem here is most people do not understand tolerance and what it means. Many assume that tolerance involves not believing your worldview is the true way (or the only true way) and in so believing, you cannot promote your worldview over others. However, this in itself is a worldview and is being promoted as superior over a worldview that believes differently. So, in that definition, a person holding to this view is being intolerant.
Such a worldview is illogical. Even Atheism, in the sense it does not believe all worldviews are equally true, is not illogical on those grounds.
So, is a Christian who tells people that the Christian worldview is the only true worldview and that all others are false being intolerant? No, they are not.
In the US, the Constitution guarantees the right to practice whatever religion you see fit, however, it doesn't guarantee the right to not have your views challenged in the public marketplace of ideas and it doesn't mean the challenge itself is equal to religious intolerance. If you have the belief, you should be able to defend its' validity and then, go have a cup of coffee with those you disagree with.