Synonyms of parochial, "characterized by an unsophisticated focus on local concerns to the exclusion of wider contexts", may serve. Such synonyms include confined, insular, limited, local, narrow, narrow-minded, petty, provincial, regional, small-minded, isolated.
Insular, for example, has a sense that means "separate or isolated from the surroundings; having little interaction with external parties; provincial." Narrow-minded and small-minded are of course easily understood, and so would be close-minded.
Blinkered, fitted with blinkers, or "eye shields attached to a hood for horses, to prevent them from seeing backwards and partially sideways", is another possibility, as are formations from synonyms blinders and winkers.
Edit: Also consider monomania, "excessive interest or concentration on a singular object or subject" or "a pathological obsession with one person, thing or idea"; obsession, "compulsive or irrational preoccupation; an unhealthy fixation"; idée fixe;
tunnel vision, "an extremely narrow point of view; narrow-mindedness"; and locked-in.
Best Answer
The word for the fear of frogs is batrachophobia, although Wikipedia suggests it is ranidaphobia. However, the suffix -phile is Greek, and there is a "rule" that the components for such a word should all be from the same root language, rather than mixing root languages. (This is really more of a common style choice and not a grammatical requirement.) The Classical Greek word for frog is batrachos (and rana is Latin). So, following that logic, the Greek word for frog should be used (rather than Latin or anything else).
So, I think the purist answer for someone who loves frogs would be batrachophile.
The don't-care-about-mixing-Latin-and-Greek answer would be ranidaphile (with the advantage that this connects with ranidae, the scientific term for the most common frog family).
The who-cares-about-disguising-English-with-smart-sounding-words-from-dead-languages answer is frogophile.