Gambit, it’s hardly my fault that you missed what I was arguing… it was there in black and white a few pages back! If it seems like Dr. Seuss to you, imagine how it feels to me, repeating myself over and over… I feel like Sam I Am, but in a really boring Philosophy 101 class. 
And I get that what yoyodoc is saying makes sense not only to you, but other people too. That’s often the way of the world… rhetoric is a pretty big stick, and when you hit people with it, logic doesn’t matter so much anymore. We see it every day. I can accept that it’s the way of the world, but I don’t have to like it and I definitely won’t drop valid logic in the face of rhetoric. There are thousands and thousands of times in our lives that we agree with something because it “seems to make sense” and doesn’t require much critical thinking. “Well, that resonates with me. It’s how I feel, too. That’s what I’m going with” is a pretty expected default reaction.
Your own counter-example can be addressed. Chik is not a word in English, so it should be pronounced as intended for an English audience, which is “Chick”. The famous example of Ghoti has been addressed by smarter linguists than me, and it’s accepted that based on our (sometimes wonky, but still applicable) rules, it should not actually be pronounced “fish”. However, if One Drop came out and said, “We know about the linguistic debate, which is a bit of an office in-joke for us! We like to call it “fish” to spite linguists and you should, too,” I would also call it “fish” with a wry grin on my face.
“Phenom”, however, is also just a word in English with two alternate pronunciations. There’s no inside joke or conscious thought to selecting one over the other. I’m willing to bet my neck nobody ever sat down and said, “Look… there are two pronunciations out there… Mickey, which one should we enforce?” Nobody would or should really care and nobody would be interested in “enforcing” it… they just want the yoyo to sell. And when the name was chosen, the people in the room likely just took it as a given that “fih-nom” is correct. People who typically pronounce “phenom” with “fee” are perfectly justified calling it the “fee-nom-ism”. Some of the same who want to do it the “Mickey” way as a hat-tip (or whatever) will do so without blinking. If you see the English word “phenom” and say it “fih-nom” aloud, I can’t think of a reason in the world you’d ever question that pronunciation.
So, full circle: it doesn’t matter what Mickey says. You have your own reasons for pronouncing it “fih-hom” (although I could have sworn more Brits were inclined to say “fee-nom” when talking about sports prodigies… luckily, you get to be on-board with YoyoEngland and call it “The Tomahto”, thus avoiding any frivolous debates).
But you should be able to spot the difference between, “I will pronounce it that way because Mickey does” (which is fine), and “I will pronounce it that way because it is correct. And it is correct because that’s the way Mickey says it” (which is what yoyodoc is arguing, and which is invalid). In formal logic, there’s a world of difference between those. To the person who don’t give a ____, they probably seem pretty much that same.
That’s the part that sends me reeling. That it’s the ONLY part I’m focusing on and yet you’re inviting me to focus on it! It’s like my saying “that’s not true or valid, Mo” suddenly causes everything else to go in one ear and out the other and you repeat, “but listen to what I just said.” “I did. I know what you are saying. And it’s a logical fallacy.” “Wait just a moment here, and focus on what I said, though.” sigh… I feel like an Abbott and Costello skit for an audience of none.