It's cool, I really don't have problem with your opinion. I know some guys that are also very strict on what they consider a real Tele, strat etc... it's fine.
But the fact remains that Telecaster is the name of a
series of Fender guitars, currently with 74 models on their line. Do they all sound like the original tele? Of course not, but that's exactly the point. If you feel that the Tele shape and vibe suit you best but you need a different type of tone, they have a guitar for you.
I think that's a weird discussion to have on the Seymour Duncan forum, since SD is a company that
specializes in making your favorite guitar sound any way you want it to sound. Technically, if you take a stock Tele and put a Seymour Duncan pickup in it, you are already changing what the classic Tele tone is. That's not a bad thing though, and doesn't disqualify your guitar from being a Tele.
At the end of the day, we should not be so concerned about what the "Tele tone" is but how to get OUR OWN tone out of one. And if to get that we need to buy a different model Tele or customize a stock Tele to our liking, hey it's all good. The guitar is still a Tele, just set up to your needs or musical style.
I'd be upset if Fender discontinued their classic Teles and replaced them with hot-rodded models only, but they're not doing that, they're keeping the classics and ADDING other options to their line. More options is not a bad thing, specially when the original is still there.