To answer your question, your homescreen has to know about WiFi state to be able to present you with information about it. That's why they're related.

As to why this is problematic, well, there's a combination of a few things going on. (YMMV, I'm summarising things from memory and I didn't actively work on this much myself)

Problem number one is that connectivity is a little more resource intensive than it needs to be right now. That's already fixed in the pending update. Problem number two is that peeking toggles the connection indicators on the homescreen, which causes a cascade of effects to mess around with touch interaction:

- peeking toggles the connection indicator on the homescreen
- this causes a bunch of synchronous dbus traffic, and disk writes
- this blocks the GUI thread of the homescreen for a little too long
- this causes evdev's kernel-side ring buffer to overflow, causing touch state to get lost in an undefined, bad place when the GUI thread finally does resume.

The situation should be improving with (near) future updates.