As a gay man, and bottom, i can tell you, huge dicks are magnetic, they are atractive, when you look at a big dick something inside you yells, go take it, suck it, lick it, put in on your face. Big cocks are tasty, delicious to suck it feels like they invite you to sit on them BUT they can be really harmfull. Maybe this guy found himself being merciless hammered by another guy's big cock before and he ended hating them.
The perfect size for an average bottom range between is 6~8 inches long and 6 inches girth. More than that can be a torture.
If you are a top, and you want to understand bottoming, the easiest way is to bottom yourself one time with a decent sized guy, once he hurt your ass you will learn to be more considerated, caring, protective with bottoms.
They also want you to merciless hammer their asses with your big cock, be sure of it, but it requires preparation, the best thing for you is to start slow in missionary, lots of kissing on the neck, ears and nipples, put it inside slowly untill you go ballsdeep, once ballsdeep let it be there for a couple of minutes and devour his neck, once the bottom is acostumed to your size, relaxed and turned on by your kisses, he will become a hungry bottomless pit for your big cock moaning "harder daddy, deeper daddy, give me your seed daddy"

EDIT: Also, bottoms love a dominant strong man, but yet protective and caring, treat him like he were your little pretty treasure, caring for his pain and being the source of his pleasure and you will literally OWN HIS ASS. Trust me