No, while abstractly “X is an asshole” can be a statement of literal fact, in the concrete case where X is a person capable of bringing a defamation suit, it is not realistically possible that “X is an asshole” can be interpreted by a reasonable member of the audience (listener, reader, etc., depending on media) as such a statement; it clearly is a subjective statement of opinion of character.
Meanwhile, a pedophile is something that a person capable of bringing a defamation suit could also literally be, and where a reasonable member of the audience for a description of them as such might (given the right other circumstances) view the description as a literal fact claim.
"This guys is an asshole" is pretty clearly a subjective opinion I hold about a person, one that others might disagree with.
"That diver is a pedophile" is pretty clearly a factual statement, implying that the person abuses kids, or has been convicted of such. (I know that, uh, the original statement was basically just an insult, but: it does posit a fact.)
The judgments in these cases take all of the context into consideration.
In general, though, accusing someone of pedophilia is substantially more serious than calling them an asshole. The former has objective meaning and can be associated with crimes against minor victims. The latter just means you don’t like someone.
Everything anyone says is an "opinion" according to some definitions of "opinion." The distinction here is whether something is a claim of fact or simply a claim. A claim of fact is something that can be verified through some sort of objective measurement or detection.
"Some pigs fly," "Bill Johnson signed over his rights to the song," and "This fish is 3 pounds, 4 ounces" are claims of fact.
"Some pigs are beautiful," "Bill Johnson writes too many songs," and "People who catch fish are probably the same type of people who support terrorists" are just claims.
Meanwhile, a pedophile is something that a person capable of bringing a defamation suit could also literally be, and where a reasonable member of the audience for a description of them as such might (given the right other circumstances) view the description as a literal fact claim.