Deconstructing Glee says that Glee itself is conservative in some ways, but to me it's definitely not conservative in the way that we describe political conservatism here in the U.S. It appears that it's getting heavily censored by the network, but some of its messages are very liberal indeed, and it's a political show in "the personal is political" way and in other senses. A lot of the sex occurs offscreen, but there's frequent talk of sex. It's certainly not all positive, as Quinn has the consequence of teen pregnancy. The show can get very dark around consent issues, including with Puck and his "cougars." I think that can be easy to miss, though. The censorship seems to be mostly around same-sex couples' displays of affection, but Glee has done so much for gay visibility, and brought up so many issues that people in the GLBT community itself were touchy about talking about, and made them mainstream discussions.
(Adding here: I had my opinions on various of those GLBT community issues, but I knew I couldn't speak for gay guys when it came to issues in the gay community. I felt it was better for me to be very cautious when conversations approached those issues. I also knew very well that I couldn't speak for lesbians or trans* folks, either. When the discussions were being had by people all across the sexuality/gender spectrums, that's when I started talking more.)
The episodes that included drinking have shown some of the bad effects that can come from excessive alcohol consumption. Admittedly it's shown them in some funny ways. There's drug dealing from a very unsympathetic character, Sandy. Puck put marijuana in cupcakes, which seemed to be portrayed more for entertainment. The Celibacy Club was a joke. The students sing fantastically inappropriate songs sometimes and at times only Sue seems to care.
A conservative version of the show would take out a lot of the talk about sex, and very likely only have straight characters. There wouldn't be talk of homophobia and bullying. That show wouldn't bring up the topics of racism, sexism and disability the way Glee does, either. With Glee, just because a supposedly sympathetic character says something, it doesn't mean that the powers-that-be of the show agree with it, and I think that gets missed sometimes. None of the characters always say the right thing, and some come from positions of privilege. The pointing out of privilege would be taken out of a conservative show. The cultural appropriation would become less ironic. Well, less deliberately ironic. It wouldn't ever be mentioned.
There are things on Glee that are supposed to be horrifying, like those consent issues, for instance. There are unreliable narrators. Those narrators would be replaced with narrators who are meant to be reliable. There might still be horror about consent issues, actually. It wouldn't be presented the same way. But a show without the darkness and irony under the entertainment wouldn't be the same thing at all.