Leaving aside the question of what "exact logic" refers to (you seem to mean the certainties of formal, mathematical logic), your question still hinges upon the meaning or characteristics of a "language that has an exact logic." Would that mean a language in which all syntaxically correct propositions display "exact logic"? Ie a language in which good grammar would always ensure "exact logic"?
If that's what you mean, we can consider Chomsky's famous proposition: "Colorless green ideas sleep furiously", from his 1957 book Syntactic Structures as an example of a sentence that is grammatically well-formed, but semantically nonsensical.
It is not specific to English, obviously, but a general fact: one can construct grammatically correct yet nonsensical sentences in any human language. One could translate Chomsky's sentence above into pretty much any human language: Les vertes idées incolores dorment furieusement.
Now for your question about philosophers who would trust natural languages' inherent logic a bit too much... I cannot think of an example. Historically, I think the general tendency of philosophers has been to do the exact opposite, i.e. to mistrust natural language, as a constant source of confusion and approximations, and (sometimes) to propose their own language instead, their jargon, supposedly more precise.
I also believe this is a bit unfair.
There is a logic to language, or rather: a language has its own logic. Not exact of course, but ambiguity has its advantages.
Vagueness requires less resources than exactitude, which will in any case always remain elusive. What is required in human verbal communication is not perfect exactitude or precision (an impossible aim anyway), but only a sufficient degree of precision for the problem at hand.
If we are eating at the same table and I ask you to "pass me the salt", you will understand me just fine, in spite of the formal ambiguity of my request. I don't think I need to ask "wouĺd you grab in your hand the small metalic container in which there is some NaCl salts, move your hand towards me and release the container on the table some 40 cm in front of me so that I can easily access it without having to stand, please, because I would like to add some Na Cl salts to my dish". That'd be overly precise for the problem at hand.
All this to say that there is a reason, a logic, for why natural languages are vague and extremely flexible. It's a feature, not a bug.