It's strange to read through this thread. There seems to be an almost cultist psychology among those who are taking the drug.
Whether that's to appease their own subconscious anxiety with regards to taking it and the potential effects, or to persuade others to join them to normalise and share that burden with them, as people feel more comfortable if others are in the same boat, who knows.
As someone in the bio field of study, I certainly would not put your faith in pharmaceutical companies to look after your health, it's a business. I still remember a professor telling me years ago, that if we went onto PhD study, we would never trust anyone again, due to critically evaluating clinical studies/research and the things which go on which violate many ethical/moral codes. Just because trials etc have been done does not mean you will not experience substantial negative outcomes.
Moreover, there are ALWAYS side effects. If you make any change to your biology, whether that be upregulation, inhibition of a pathway/enzyme/protein etc, there is always a cascade of knock on effects.
The only debate is whether the balance of those effects is positive enough for you to take the drug. Does potentially keeping your hair outweigh the potential negatives. These negatives should not be downplayed since your hormones are absolutely paramount to your biology, substantially reducing DHT is not something you should consider lightly.
It's quite shocking to see how flippant people are about taking finasteride. Would they feel the same about altering DHT in the other direction by injecting anabolics for example? Does the method of adminstration, a simple tablet as opposed to injection, give an impression of less significance of what you're doing? Possibly.