Hedonism is a philosophy that posits that pleasure is the sole objective good and thus pain something bad.
This whole thing is about trying to find shortcuts to get to the pleasure of having a nice body while circumventing the pain and effort.
Pain and efforts are important, they forge character like nothing else. If you want to live in a world where adult-children simply take their soma to get what they want, you're just not thinking about the consequences.
Do you feel this way about everything? Like you shouldn't take an aspirin because you should feel the pain of your headache? You shouldn't wear shoes because you need to feel the pain of the rocks under your feet?
Why is this particular thing the bad thing?