"I disapprove of what you say, but I will defend to the death your right to say it."
At no time in history has there ever been a philosopher who respected or accepted all ideas as equally valid, including those which are dynamically opposed to their own. That includes Voltaire. The quote in context is not saying that all opinions need to be respected. It is saying we should defend the rights of others to have alternative opinions. Alternative opinions which we can then challenge and attempt to invalidate through a process of argumentation.
I feel the same way. Say whatever you want in any way you want to say it. But don't expect that if what you say is nonsense I am not going to point that out. I am actually going to enjoy myself destroying your opinions and ideas through logical and behavioral analysis.
Now, let's put the quote in its proper context, shall we...
Voltaire did not say that at any time, nor did he popularize the saying. The quote comes from a book, "The Friends of Voltaire," written by Stephen G. Tallentyre--which was a pseudonym of Evelyn Beatrice Hall. It was hard for a woman to be published in her day, so like a few female writers, Evelyn used a man's name to write under.
The quote above was spoken as a summation of Voltaire's attitude and is often misread as being a direct quote from Voltaire himself.
This is an actual quote from Voltaire:
"What is tolerance? It is the consequence of humanity. We are all formed of frailty and error; let us pardon reciprocally each other's folly--that is the first law of nature."