This subject is so vast you could write for hours. Everyone does better using different approaches. Obviously if a guy is terrified of putting on any fat/water he is never going to be as big as he can be. The opposite can be said for guys who try to get as big as possible eating everything in site and they hit a wall and they put on unnecessary fat. I could go into detail but there is no real point but if I were to things such as digestion, insulin sensitivity, inflammation and well being would be mentioned.
Genetics vary massively. Even if you aren't a genetic elite your body type and metabolism are huge factors. When I was younger I could have ate anything because I was tall and skinny and struggled to gain weight until I took in a huge amounts of calories. There is a limit to everything though and say I did eat everything in site including junk food it would eventually slow down. Forcing food down over years has a bad effect. Many of the guys who done that may have gotten big and even lean but they have blown out waists and it only went against their look.
Some guys don't have waist genetics on their side so even with careful eating and gradually moving up in calories over years and doing everything correct they still have wide waists. Some guys have great genetics and can get away with much more. It should go without stating anyone force feeding huge amount of food (especially junk food) over years is going to have a host of issues down the road (heart, cholesterol, kidneys, liver, insulin etc). There are things you can do to mitigate that damage but no matter what eating like that especially when combined with pushing drugs will only damage you.
I am all for pushing things but there has to be a limit and things need to be done over time. Just like you shouldn't double your doses over night you shouldn't double your food. Some people actually do better with some junk food in there but what people consider as "junk food" can be very different. Fried chicken and a grilled beefburger are very different things. 80 pieces of sushi and 20 pieces are also very different. You only live once so if you enjoy some junk food have it but once every 2 weeks is different to once daily. This is all basic stuff with the point being every situation is different and eating clean doesn't have to mean never having "treats".
The answer for many usually lies somewhere in the middle. It may take longer but you will feel and look better by the end of it. Most of us wanted to push up in weight in the past and get as big as possible (within reason) and there are many ways to do that. But none of the guys I know who pushed everything and got really fat in the process are doing too great now. Some people can get away with it but most can't. Even the gentic elites can't get away with it because many done that and pushed the size at all times and they were told the guts on stages are getting out of hand.
There has to be balance and anyone who values an aesthetic physique should never force food. If you are having issues with appetite/digestion/bloating you should find out why you are having those issues. Obviously your body doesn't want to be 260 pounds and lean so sometimes you have to force a meal down so I don't want to mistake my meaning of forcing food as that to me is a long term thing. Sometimes you may not want to eat and it takes some effort but if you are constantly bloated and forcing food that's not doing you any good in the long run.
OP reading your other posts and I agree. A lot of bodybuilders just copy so they eat chicken and rice all day and it doesn't have to be that way. I think the issue for most is a lack of cooking skills, creativity with food and knowledge of bodybuilder friendly foods. Chicken and rice over and over is just boring but it can be effective. If however you get bored and struggle you could make a giant soup/broth. Fill it with loads of chicken, barley potatoes or rice, various vegetables etc. Make homemade lower fat burgers with sweet potatoe fries. Make a lower fat high protein spaghetti bolognese with loads of herbs and spices. Throwing these type of meals in with your meat, rice and veg/fruit meals and you are onto a winner. Not eating "clean" doesn't have to mean eating dirty.
Sorry I just rambled on with this post but I think I got it back on track