Why would someone "with his standing at Harvard" be expected to avoid "wild, and public, hypothetical[s]"? Does everyone at any prestigious institution have so

Why would someone "with his standing at Harvard" be expected to avoid "wild, and public, hypothetical[s]"? Does everyone at any prestigious institution have some duty to remain conventionally mundane in all their musings? Is there any reason to think such hypotheticals are, on net, more harmful than helpful? Isn't tenure (like Loeb's) designed to encourage a fearlessness around topics & speech?