A 'bop' to me is a really, really catchy song that is commercially successful and loved by the GP. They're usually 100% pop and chart really well on the Billboard Hot 100.
To do this requires a lot of skill and talent. You have to understand pop music, current trends and what will work. People on here constantly dismiss bops as being 'generic' but it actually takes a lot of musical skill, songwriting talent and amazing production to produce a certified bop. And if it was so easy to produce a "generic" 100% pop song that charts well, then everyone would be doing it. Every artist cares about the charts and how commercially successful their music is.
The GP and commercial success reflect what makes a good song more than any critic or biasedT stan on ATRL does.