Yes, it is discriminatory in the (irrelevant) broader sense that it involves "recogniz[ing] or perceiv[ing] the difference." Of course, that renders the context meaningless. A more appropriate definition--the "unfair treatment of a person or group on the basis of prejudice"--preserve the proper connotation conveyed in Trumbull's remarks.
"If a male or female human being is denied the right to marry a male or female animal, [and] a male or female animal is equally denied the right to marry a male or female human being[,] I see no discrimination against either."
This assertion is sound enough to most people. However, indefensibly invoking a shallow case of special pleading leads us to question deep principles delineating proper and inappropriate relationships (i.e., consent).
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