As you said - people are bad at low ranks. This is true. There are ranks which tell the skill level of that player.
Now the orginal question was is hots skill or luck based game. Some people said it is based on luck. Well you just said people are bad at low ranks and bad means literally they have low skill. If skill dont matter in hots it would be irrelevant if someone is bad. Therefore hots is skill based game.
Some people got this delusional mindset at lower ranks that luck has more to do with the game than it actually does. The reason for this is that they lack self critism and self awareness. They are not able to understand their own misstakes in game and the impact within those misstakes. It creates false, delusional view that game is based on luck which in reality luck plays a lot smaller role in the game many believe in.