A lovely idea until you realize what is necessary to enforce these ideas on those you don't find adequately cooperative. The catch here is the word "all." No dissent can be tolerated or the whole thing falls apart.
Just look at the increasing demands that those who disagree with enforced "tolerance" towards the "gay agenda" be silenced.
If they are going to have tolerance for all, they must by definition enforce it by being intolerant of those who aren't adequately tolerant. In fact, they will quickly move beyond requiring tolerance, in its true meaning, and enforce acceptance and even celebration. Eventually even silent acquiescence will not be enough, they will try to enforce open and outspoken approval.
The problem with being absolutely sure you are right (even in the pursuit of virtue) is that by definition anyone who disagrees with you must be absolutely wrong, and probably evil. Idealists always end up as tyrants. For a good example of how this can work, look up: http://www.youtube.com/watch?v=ej5rceb4-hQ&feature=related