How was using HGH prior to 2005 when MLB banned it considered cheating? I'm pretty sure to cheat at something that require's you do something that's against the rules and gives you an unfair advantage, which he didn't.
Prior to 2005 all players were free to take HGH as they wanted. Pettitte also said if had been been banned back then he wouldn't have taken it.
Was it stupid? Yeah, it was stupid. Was it desperate? Yeah, it was probably desperate. Was it cheating? No, I don't think so.
Comparing Pettitte and Manny is like apples and oranges. Manny took actual steroids, which were banned by MLB since 1991. Manny gained a huge amount of muscle/power after he started using them.
What Manny did was cheating, just like Clemens, Giambi, and A-Rod who all took steroids well after they were banned.
My post above addresses why I don't think players who took HGH prior to 2005 were cheating.
What did he lie about though? I agree with you about him being a hypocrite, but that's about it.