Sure. Trump calling CNN fake news, etc. Religious groups banning the study of other religions or philosophies. People who denigrate the opinions of others because of their social status, bad grammar, political affiliation, etc. Scientific papers whose introduction is a concerted attack on the opinions which came before them. Those opposed to Trump who claim some superiority in their ideas on the basis that Trump is a serial liar, in the pocket of Putin, etc.
When you support your idea through making another idea or person invalid, it is a definite indicator that you are going wrong somewhere. It doesn't necessarily mean your idea itself is wrong. It might mean you're defending against some uncertainty, fear of losing social status, or a whole number of other reasons. But it isn't necessary to destroy or suppress another for you to be valid. When you succeed in doing so, it closes you off to the opportunity to challenge your own self which might lead to transformation or enrichment of the idea at hand, even if you are knowingly challenging yourself with something flawed.
For example, those that might attack the wall as a bad idea. Well, I've heard few actually analyze the wall itself rather than focus on Trump's and others' behavior. Logically, it seems to me that building a wall at the southern border would reduce illegal border crossings. There is potential merit to the idea. I still thing it is the wrong idea because when I have looked at data on the benefit and harm of those who enter the country on the border not through legit ports of entry, I don't see a compelling reason that this is bad for the country. Certainly not enough to warrant the cost. Beyond that, I think the cost of the wall in terms of promoting xenophobia and isolationism internationally themselves are undesired and more significant than any impact it might have on immigration. That's why I'm opposed to the wall. As for the parts of Trump's and other's behavior on the matter, this is a separate matter and I think is leading the country to worse and worse governance, greater division, and poor ethics. These are among the reasons I desire real action to stop Trump himself.