There is a word for that!

Your new word for today. Use it wisely.

 

Do not ask who the word describes, for it may describe thee.

Philodox 
A person who loves or vehemently propounds his or her own opinions; a dogmatic or argumentative person.

First use.

1603   J. Florio tr. M. de Montaigne Ess. ii. xii. 313   No people are lesse Philosophers..than Platoes Phylodoxes, or lovers of their owne opinions.