The response is Gzipped, so there's no point in trying to decode it as UTF-8. You can either decompress it yourself:
from io import StringIO
import gzip
with gzip.GzipFile(fileobj=r) as handle:
html = handle.read()
Or use something like Requests, which does it for you:
import requests
html = requests.get('http://www.stern.nyu.edu/', headers={
'User-agent': 'Mozilla/5.0'
}).text