If someone is trying to gain weight, should they be eating high calorie foods even if those foods are high in sugar/fat?
It depends on how they want to gain. If they want to just be heavier without regard to fat or lean body mass, then it doesn’t make any difference whatsoever. If they want to gain LBM, then they should focus on protein first, then healthy fats and carbs. But they also must be doing sufficient resistance training to build muscle.
You can lose weight on the Twinkie diet. You can gain muscle on the Twinkie diet. But that does not make the Twinkie diet a wise decision, because there is more to health than the number on the scale.
Healthy High calorie foods are a great idea if your appetite is small and you‘re trying to hit your calorie goal for the day.
Don’t use „i‘m on a bulk“ as an excuse to eat unhealthy meals. If you want to eat a pizza every now and then by all means do it, but don’t fool yourself anyd think you’re doing it because there is no other way to get those calories in.
In my opinion there is not a single reason to eat unhealthy, unless for pleasure.
You’ve essentially described “dirty bulking”. The quality of food is important for your health. It may be easier to gain eating junk food, but are you better off? You can increase calories from healthy higher calorie sources like nuts, seeds, avocado, liberal use of EVOO, and lean meats.