"Incontrovertibly true!" "The discussion is over." "The debate is settled." "The science is conclusive." "Virtually everyone agrees." "Only the ignorant or uniformed would disagree."
Statements like the ones above are meant to restrict our thinking and to muzzle our mouths. Attempts to scuttle our curiosity or to thwart honest skepticism are frequently used techniques of the dogmatically entrenched.
Dogma is a belief adhered to zealously (contrary evidence be damned). Dogma leaves no room for doubters. Dogma marginalizes all others. Dogma requires strident conformity. The dogmatic are often willing to discredit, disparage, or impugn any who would disagree. Their position is that there simply is no room for dissent.
WARNING! We should be most suspicious of anyone who would extinguish or censure skeptical inquiry. There's most certainly some nefarious reason they don't want us to ask questions.