Is it, though? I mean, really? In an ideal world, I would absolutely love to agree with you.
But, aside from certain forms of speech (hate speech, illegal speech, etc.), Twitter is pretty hands-off with what it allows. So it has given "sunlight and exposure" to people like Trump, and what has it gotten us...? Trump. A man who has used racism, sexism, xenophobia, lies, and false promises to win the US Presidency, and who used Twitter as a major platform for spreading such. How has sunlight and exposure disinfected his toxicity?
Now, sure, doing otherwise would definitely be silencing an opposing view point. But... when that view point is so toxic, why is that necessarily bad? This might be a controversial opinion for me to hold, but I don't believe all view points are created equal, and I don't believe all view points deserve to be heard, or, more to the point, deserve a platform to be heard. I'm not saying choosing is easy, and not fraught with moral peril, but I think the idea of this big free-flow of ideas being the ideal, given the constraints and issues with our society, is... frankly, a little naive.