I will grant that possibly he was just sloppy in how he expressed himself, not being careful enough to NOT imply he was dismissing the Ten Commandments. But that is certainly how many very reasonable people heard when he spoke. I will not judge if it was anything more than a mere oversight on his part, but I do understand how others can believe otherwise - there is so much watering down of “old standards” in biblical teaching today, and ministers not intending that need to be careful that are not misleading their flock into it.
I think the problem is, people see the Sermon on the Mount as being easier to manage, and it’s squishier, IOW, more feelings based and being *nice* and accepting and kumbaya, where the Ten Commandments come across has absolutes and people portray them as harsh and condemning.
So doing the Sermon on the Mount seems nicer, on the surface, more accepting, etc, but in reality, the Sermon on the Mount sets the bar far higher.