Subie Rumble's video: 2003 ZX6R Won t Start 2 New Battery Fix

Bike is a 2003 Kawasaki Ninja ZX-6R 636cc 15,000 miles Watch the video to see what I did in regards to checking & confirming it may be the starter. So after reading all your feedback on what the problem may be, I decided to replace the battery to see if this fixes the issue... Engine still won't start or turn over. I checked the voltage of the battery, starter solenoid & the wire that actually goes to the starter itself. All were getting voltage, however the starter still wouldn't turn or spin. Just made a squealing noise (as heard in the video) & that's it. So I think I'm going to replace the starter now but I would like to hear your thoughts first! I've had two people already mention a seized engine. Can someone elaborate on the matter? Is this actually a thing I should be considering being an issue? In case anyone was wondering, you need to remove the faring, gas tanks & coolant reservoir to get to the starter. No need to drain oil or anything like that. Thanks for the help! As of right now, I think I'm going to replace the starter & hope that fixes the issue. Oh & I suppose it may be worth mentioning that now that the starter is out, I can spin the starter gear by hand, it doesn't spin freely (not sure if it's supposed to) but I can turn it by hand so it isn't mechanically stuck.