What's a word for someone who wants to voice opinions but not have them challenged?

Perhaps dogmatic?

Merriam-Webster: "expressing personal opinions or beliefs as if they are certainly correct and cannot be doubted"

or, upon looking for synonyms for dogmatic, there's doctrinaire:

dictionary.com: "dogmatic about others' acceptance of one's ideas; fanatical: a doctrinaire preacher"

I think self-rightous may fit:

• confident of one's own righteousness, especially when smugly moralistic and intolerant of the opinions and behavior of others.

I would suggest autocratic, which is defined by oxforddictionaries.com as “taking no account of other people’s wishes or opinions”.

My suggestion is a verb, but I think pontificate is a word that describes what this person does.

Per Wordnik, there are these definitions:

To act like a pontiff; to express one’s position or opinions dogmatically and pompously as if they were absolutely correct.

To speak in a patronizing, supercilious or pompous manner, especially at length.

Pontificate has the connotation that the person has spoken, and he or she will brook no argument or further discussion.