The evangelist who ignores anything outside their own agenda-sphere is either too ignorant to deserve attention, or too disingenuous to be trusted.
I listened to a Microsoft evangelist talk for more than an hour about web development, and you would have legitimately thought that .NET was the only web-development platform on the planet, and that everything was deployed to Windows Azure Cloud.
I've listened to religious evangelists who skip selling their faith as the “one true way”, and just ignore that there could be any other ways at all.
Do yourself a favor, learn about the other side. Nothing is one dimensional. Play devil's advocate. It'll only strengthen your conviction, your message, and your powers of persuasion.
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