This may be a matter of semantics but, inasmuch as halacha is defined as what one should do in any given scenario, the answer to 1 is necessarily no. This isn't to say that halacha is "one size fits all". On the contrary, the nuances of each individual case are what define its unique ruling. (This is the prime motivation behind the AYLOR caveat prevalent on this site.)
With regards to 2, it depends. Were the person higiya l'horaah (has sufficient moral and legal understanding of halacha), yet the majority of the halachic authorities (e.g. the Sanhedrin) have ruled without the benefit of his unique wisdom (which he, without any hubris or naivete, understands to be so compelling as to be beyond argument), he would be remiss to supress his unique moral knowledge, whether by his own actions or by withholding his information from the halachic authorities (see e.g. the first daf of Horayos and Rishonim including Ramban and Tosfoth HaRosh; See also Rambam, Hilchoth Mamrim Ch. 1-3).
On the other hand, if his is a vaguely defined moral intuition, utterly lacking in the nuance that defines halachic reasoning, and tainted by the mores of an outside culture that condones barbarity and perverseness that are antithetical to true morality (as is suggested by the language chosen by the "rabbi" you cite), the issue is primarily with his hubris, naivete, and his understanding, not only of "morality" but perhaps of halacha as well.