Back in the 1980s, that stuff (Kiss, 5150, etc) was heavy metal. At least that's how I saw it as a teenager in 1984. IMO, if it was in Circus Magazine, then it was heavy metal. Before I got into Metallica, Anthrax, Pantera, etc... it was all about bands like Quiet Riot, Def Leppard, Ratt, AC/DC, Judas Priest, Rainbow, KISS, etc, etc etc .....
That's the way I looked at it as well & I can even recall a "Heavy Metal" themed issue of Creem in the late 70's & it featured Kiss, Queen, Nugent,Aerosmith...
In the 70's Aerosmith,Nugent,Kiss,Judas Priest, Scorpions, AC/DC, Queen all were considered Heavy Metal. By the mid/late 80's the sub genres of metal were in full force you had Speed Metal, Death Metal, Glam Metal, etc & then sometime after that a lot of these bands were just considered "Hard Rock". As Jesse said it's all Rock & Roll & that's how I look at it.
Of course you can say "I Was Made For Loving You" isn't heavy metal but does that mean forget about Kiss Alive & Creatures of the Night because Kiss isn't metal because of some songs. What about "It's Alright" from Sabbath's 'Technical Ecstacy' album or "Laguna Sunrise" from Sabbath Vol 4?? Does that make Sabbath not a metal band??? It all boils down to your opinion & that's what Spacelord was getting at when he made his rule
Rhino Records released a phenomenal Heavy Metal Box set a few years ago & I feel that was a great guideline for Heavy Metal.
Here's the setlist:
1. In-a-Gadda-da-Vida - Iron Butterfly
2. Summertime Blues - Blue Cheer
3. Easy Livin - Uriah Heep
4. Highway Star - Deep Purple
5. Billion Dollar Babies - Alice Cooper
6. Lost Johnny - Hawkwind
7. Bad Motor Scooter - Montrose
8. Working Man - Rush
9. Man on the Silver Mountain - Ritchie Blackmore's Rainbow
10. Detroit Rock City - Kiss
11. Ripper, The - Judas Priest
12. Cat Scratch Fever - Ted Nugent
13. Lights Out - UFO
14. Godzilla - Blue Oyster Cult
15. Demolition Boys - Girlschool
16. White Witch - Angel Witch
17. Phantom of the Opera, The - Iron Maiden
18. Neon Knights - Black Sabbath
Heavy Metal Box Songs DISC 2:
1. Ace of Spades - Motorhead
2. Am I Evil? - Diamond Head
3. Nice Boys - Rose Tattoo
4. Attack of the Mad Axeman - Michael Schenker
5. Denim and Leather - Saxon
6. Blitzkrieg - Blitzkrieg
7. Gangland - Tygers of Pan Tang
8. Witching Hour - Venom
9. You've Got Another Thing Coming - Judas Priest
10. Number of the Beast, The - Iron Maiden
11. Star War - Raven
12. Say What You Will - Fastway
13. Black Funeral - Mercyful Fate
14. Animal (F**K Like a Beast) - W.A.S.P.
15. Mean Streak - Y&T
16. Holy Diver - Dio
17. Queen of the Reich - Queensryche
18. Whiplash - Metallica
Heavy Metal Box Album DISC 3:
1. Rock You Like a Hurricane - Scorpions
2. Metal Health - Quiet Riot
3. Into the Fire - Dokken
4. Balls to the Wall - Accept
5. Round and Round - Ratt
6. I Wanna Rock - Twisted Sister
7. Boulevard of Broken Dreams, The - Hanoi Rocks
8. Big Bottom - Spinal Tap
9. Midnite Maniac - Krokus
10. I'll See the Light, Tonight - Yngwie J. Malmsteen's Rising Force
11. Crazy Nights - Loudness
12. Shake Me - Cinderella
13. Watch the Children Pray - Metal Church
14. To Hell With the Devil - Stryper
15. Little Time, A - Helloween
16. Wrecking Crew - Overkill
17. Caught in a Mosh - Anthrax
18. Peace Sells - Megadeth
Heavy Metal Box CD DISC 4:
1. Still of the Night - Whitesnake
2. Rock Me - Great White
3. Talk Dirty to Me - Poison
4. Bathroom Wall - Faster Pussycat
5. Hall of the Mountain King - Savatage
6. Kiss Me Deadly - Lita Ford
7. Hail and Kill - Manowar
8. Trial by Fire - Testament
9. Welcome Home - King Diamond
10. South of Heaven - Slayer
11. One - Metallica
12. Cult of Personality - Living Colour
13. Youth Gone Wild - Skid Row
14. Cowboys From Hell - Pantera
15. Beg to Differ - Prong
16. Dead Embryonic Cells - Sepultura