Using English when it's not your mother tongue

Why would someone not use his natural, from-birth, language to convey what he has to say, and instead would revert into the usage of English?
Some Americans, Brits and Aussies find offense when someone is using "their" language for their needs. "Let them use a language that they are completely fluent at", is often used in such debate.

Well, as you might have noticed from the content of this blog, I don't possess of perfect English. I try to perfect it from day to day but it would still never be quite the same where the daily usage is of another language (won't tell you where I'm from because then you would assume, wrongly if I may say, that I am biased in my opinions).

I am using English to reach a larger audience. The internet has given us, the artists an opportunity to convey our words to a larger audience, given we are putting the right marketing strategies into being.

I chose English for you, my readers. I come with added values, vast understanding of the online marketing business, been around and know plenty. I come with a platform dear friends, I come with revolutionary ideas and if you don't like it, you can just hop to other great sites that I am fond of, using this ------> sidebar . They all are written by fluent writers, believe me.