A simple web app where anyone can add names to a tree.

So the business about "hyperlinking to a text file with more info about the person" is no longer part of the requirements. Good, because allowing random people to upload random files to a webserver without taking precautions is an astonishingly risky thing to do.

So, anyone at all? No authentication? You'll be happy to allow random trolls half way around the world to add random text into your tree? Cool.

You're happy to have no data validation? So people can hack your website by adding, say, 15GB of text to the tree as one single name, cause a buffer overflow, and hijack the computer? Nice.

"Oh that's not what I mean, of course you need to work out how to do it safely and reliably, and avoid network errors and data corruption even if the internet connection is lost halfway through an edit, and make sure the data in the tree doesn't get corrupted, and include some sort of user authentication, and all the other things which I haven't even thought of. How hard could it be?"

This tree... is it supposed to be displayed as a family tree, or just dumped as a block of undifferentiated text?

"Of course it has to be displayed as a proper tree, and look good even when the window resizes or if the user doesn't have the right fonts. It doesn't need to work on a mobile phone, just desktop, because I know that's about 100 times more difficult. Oh also don't worry about making it work on all common browsers, everyone can use Internet Explorer and like it."

If YOU don't know how to make a simple program that is YOU problem. You are either stupid or inexperienced.

Since you're so smart and know so much more than actual web developers, you should just do it yourself. Surely you've spent more time bitching about this than it would take a genius like you to actually program it.