Abstract nouns take the zero article, but when modified they take a definite or indefinite article. In this case, "respect" as a general term takes the zero article. I have respect for teachers. When modified, "respect" takes an article. I have a healthy respect for teachers. Notice these examples from the Oxford dictionary. I have the greatest respect for your brother. A deep mutual respect and understanding developed between them. RESPECT https://www.oxfordlearnersdictionaries.com/definition/english/respect_1 ​ [uncountable, singular] respect (for somebody/something) a feeling of admiration for somebody/something because of their good qualities or achievements ==>> I have the greatest respect for your brother. A two-minute silence was held as a mark of respect. ==>> A deep mutual respect and understanding developed between them. It was very interesting. Respect! (= used to praise somebody)

I think it is best to see this as an expression that is an exception.