I just wanna know. i hear that using grease/petroleum is bad for the hair.?

i have extremely dry hair and i tried using an mega thick growth oil, but once i used it i hated it. it dripped down my neck so that made me have to wipe some out my head; but i used a small amount to began with.Also it doesn't mix well with other products like gel. i have natural hair so i use gel to slick down my hair down.So i started to grease my scalp with SOFTEE HERBAL.GRO. and i have to day that it mixes great with gel and also my hair has gotten so thick and manageable. my edges have grown in so well and do to the face that my hair was so thin you could see my scalp a little means a lot. I just wanna know how is grease bad if you have good results and plenty ppl you know who has good results as well.