I've never had the problem with bitter iced tea (I usually use the sun
tea method, 4 bags to a gallon of cold water, stick it in the sun until
it looks like tea...) but can imagine problems with hot water. I have a
decent CTC assam that I drink, and it is about perfect in 45 seconds.
If you let it go more than about 2, it gets pretty bitter. OTOH, those
lipton bags don't have much tea in them, so I'm not sure how far wrong
you could really go. Sub par, yes, but I don't know if you could make
the cup all that bitter with the little bit in them.