Can someone explain what is objectionable about this answer?
The answer utterly fails to address the OP's question, it reflects the author's (i.e., your) confusion of unnecessary concepts, and it fails to at least make a point.
The entire answer barely purports to equate labels to bound variables. That depiction is inaccurate, and it gets worse by attributing to "mathematical logicians" that misconception. Not every label is a variable. In the case of labels such as Blackacre and Greenacre, they are used in reference to goods or elements that never change at all (i.e., they are constants), which is why calling them "variables" is wrong in the first place.
Regardless of the inaccuracy of that depiction, the matter as portrayed in that answer is too reductionist to qualify as a "kind of formal logic [that has applications in law]". Formal logic involves a set of axioms and rules that go far beyond the use of conventional labels. Conventionality neither implies nor is necessarily premised on logical foundations.
Altogether your answer is the equivalent of answering the question "Is mathematics a logical field?" with "It uses letters 'x' and 'y' known as bound variables".
The others who answered seem at best to think that if the law is illogical or not based on logic, then that means the law does not use logic.
You are mischaracterizing both answers by impliedly equating "logic in substance" with "rigorous/formal logic". The latter would be impractical when it comes to remedying a harm that a party causes to others. The quote of Oliver Wendel Holmes, Jr., is the preamble of his explanation of what keeps logic constrained in the field of law. But constrained does not mean completely excluded from law.
I think it's fair to think I know more about logic than do well over 90% of those who post here.
You could have made an effort to reflect that in your answer. One-liners are hardly ever persuasive, and in this case the only statement in your answer is notoriously wrong.
From the answer in its present state there is a huge gap between the bare mention of bound variables and the complex question of whether (and, if so, to what extent) formal logic has applications in law. Trying to establish that your knowledge of logic is greater than that of 90% of contributors is even more ambitious and unnecessary.