First of all, hair metal songs are much more song oriented and individual songs do a better job of maintaining song individuality and recognizability. For example, if you hear a hair metal song on the radio, most likely the name of the song and band will come to mind instantly if it is a song you are even somewhat familiar with. Thrash metal songs individually are much less distinctive. Listening to a thrash metal album, you may not even be aware when a song ends and when a new one beings. You hear a thrash song on the radio and you may be able to identify the genre or maybe the band if their musicianship is distinctive enough, but the songs don't have a particular sense of individual identity. With the low growling vocals and long guitar solos and lack of any catchy choruses or vocal melodies, it can be hard for any people, music experts to amateurs, to tell the difference.
Hair metal generally is also a lot more positive. It tends to focus on the happy, good things in life, it says that life is a nice big fun party and you should go enjoy it to it's maximum. Maybe it preaches some irresponsibility as we'll, but overall it is a kind of music which celebrates the fun and joy of life. It brings out better moods and more optimistic feelings than thrash metal does. Let's face it- thrash metal is not something you would play at a wedding or at a good natured party. Its main themes include death, violence, and pure negativity. That definitely has it's time and place, as anything does, but good feelings are generally a lot healthier than bad ones and that is a major difference between the two bands.
And now let's get superficial. Visually, hair metal was maybe the greatest genre of music that ever lived. Taking influences from Shock Rock and the early 70s glam rock, hair metal produced a look that was fun, colorful, and exciting. I'm not the only person out there who could watch hair metal videos all day long and not get tired! The musicians were mostly pretty gorgeous and I love the hair- admit it, you do too. The image of these long haired and happy looking musicians making videos that make you laugh and entertain you and being out such positive vibes, the idea of these lucky Californian boys living the dream life, it really is great. It's a great music scene visually, the visual aspect is probably greater than the music, and let's face it, the image does take a large role in a band's success and fan appeal. The whole image of thrash metal was much darker and less inviting. Hair metal said "Come party with us, we'll have a great time," while thrash metal said "Get out of here, we don't care about you." Which reception do you prefer?
I shall remind you again that in this argument I am neutral and take no side, I love thrash and hair metal, but hearing so much about how hair metal bands are garbage and so much praise for thrash is starting to bug me and I wanted to make sure some good counter arguments on the topic were made. But both genres were great and should be loved. And really, I still don't understand how music as positive as hair metal can be so hated, and as negative as thrash can be so loved. So ironic...