Indeed - this support hub page should probably specify what versions of Bluetooth and ANT are required. I’ve passed that feedback to the right team.
While Zwift mentions BLE elsewhere, the first Bluetooth Low Energy variant came along around 2012 so it’s very likely your laptop doesn’t have this hardware built in.
Lucky for you - a USB dongle that gives you that BLE capability is relatively cheap. Another possibility is an ANT+ dongle. I have an ANT dongle for my Windows laptop and if I were to recommend just one - I’d suggest you get ANT+ instead of BLE. Over time - the ANT dongle purchase will remain useful because any new laptop should already have BLE capability built in, where built-in ANT capability is still not widespread.
If you want to pair Bluetooth earbuds and play music - you could pick up both dongles, I guess?