Throwing the Baby Out with the Bathwater: Logic, Flaws and Pity

Does the quality of a statement rely on the whole ideology of it's purveyor? 

I invite you to discuss flaws in quoted context and logic.

By incorporating well-exercised logic into our conversation, we improve the quality of our conversations, thus improving the intellectual quality of the experience as a whole, and allowing us to more deeply improve ourselves as human beings.

Here is a real life and recent example:

Steven, a friend whose intellect I admire and appreciate, shared the following quote:

"If an opinion contrary to your own makes you angry, that is a sign that you are subconsciously aware of having no good reason for thinking as you do. If some one maintains that two and two are five, or that Iceland is on the equator, you feel pity rather than anger, unless you know so little of arithmetic or geography that his opinion shakes your own contrary conviction. The most savage controversies are those about matters as to which there is no good evidence either way. Persecution is used in theology, not in arithmetic, because in arithmetic there is knowledge, but in theology there is only opinion. So whenever you find yourself getting angry about a difference of opinion, be on your guard; you will probably find, on examination, that your belief is going beyond what the evidence warrants."– Bertrand Russell, An Outline of Intellectual Rubbish (1943).

I appreciated the sentiment so I shared it myself and even saved it.  Upon expressing my appreciation, Steven warned me that my fondness may waiver if I were more familiar with Mr. Russell. "He will rub you the wrong way" he warned.  And so indeed, upon reading this article to which my friend provided a link, my opinion was in-fact altered.  The article contains several quotes by Bertrand Russell in apparent support of "mass psychology" via controlled schooling.   Myself, being a long time and known advocate for intellectual freedom through uncontrolled education, I was naturally "rubbed the wrong way" by Mr. Russell's quoted sentiments therein.

However, I wonder if, upon reading the personally disagreeable piece, I should reject the quality of the original quote?

The question I pose to you is this:  Is a truth (or untruth) isolated to it's own value or is the quality of it shaped by the whole of he or she who spoke it?
Does my newly acquired knowledge about the man's work - with which I disagree - mean that I should reject the isolated sentiment with which I do agree? Has it lost credibility in disagreement?

Before you answer, digest the definition of Ad Hominem fallacy and consider whether it is applicable to this situation.  And consider my response to my friend:

" What strikes me most curiously about this article is that I'm surprisingly under affected. I think perhaps I have read, talked about and obsessed over this very topic to such a degree that I've emotionally flat-lined. It certainly helps to shape a more bitter view of Bertrand; but bitter in a heady way. I *feel* nothing...but perhaps pity as one would for the unfortunate and mislead. Multi-layered irony, eh? And in the end, intellect wins; for if I were to dismiss the logic in the statement due to my fundamental disagreement with the other opinions of the mad, would be to commit Ad Hom; and that faulty logic would be on me.As to the information presented in the article; I wish I could feel shock and disgrace but the sad truth is that by this point, my emotional response to the reality of psychological propagandizing has been reduced to "Well duh." And so, the irony of pity herein remains."

Why should you do this exercise?  Because it's brain food.  It's good for us to think these things through, reasonably and logically because they help us communicate on a higher plain and improve us as human beings.  :) Thank you in advance for contributing!