Many if not most liberals routinely use disapproving labels in lieu of reasoned argumentation. These liberals will label conservatives stupid, backwards, evil, etc., then immediately move to the supposed implication that therefore people need not and should not listen to this or that position put forth by a conservative.
For example: conservatives are greedy capitalists who don't care about the poor, therefore pay no attention to any plans conservatives propose to improve the economy.
Another example: conservatives are racist, therefore whatever conservatives say about blacks, Hispanics, Asians, Native Americans, and other minorities is false.
Or: conservatives are misogynists, they don't have women's interests at heart, therefore we can safely dismiss whatever conservatives say about a woman's right to choose.
Closer to home: conservative Christians are poorly educated, anti-scientific hicks and rednecks, hence no need to consider anything they say about the theory of evolution.
Examples could be multiplied. But the point is, liberals who label in this fashion are not only illicitly reasoning, but they're behaving unethically or immorally. Indeed, these liberals are bullies.