Okay although I understand where you're coming from, I don't agree with you. you're disregarding the fact of what these characters have done. All nearly destroying equestria at will. The fact is love and tolerance can only be effective in most situations, but in cases of extremes such as those, tolerance isn't enough.
Now not only that but I believe an extent of love and tolerance is present in the first two cases. Rather than completely banishing or even something worse, the mane 6 are tolerant and loving enough to return luna back to, well luna. Even in the case of discord the mane 6 show tolerance and love. In a later episode they are willing to love discord to help reform him (which is still unclear if they were successful) but regardless. Now with the changelings, the mane 6 really had no other choice. With the stake of equestria on the line, dire measures were needed. Like the common saying goes "desperate times call for desperate measures. "
And lastly, you have to consider that a vast majority of the show, if not every episode, in one way or another, personifies those traits.
So to say that love and tolerance is completely thrown out the Window, id have to disagree with you. Because it is still present in those episodes and vast majority of other episodes still present love and tolerance