The Dunning–Kruger effect should be in play here where people overestimate how fit they are. However, it really comes down to defining where the acceptable middle ground is. The majority of adult Americans are overweight (25+ BMI) and that’s been normalized with morbid obesity being considered excessive.

“Research suggests that changes in the social perceptions of what constitutes overweight and obesity may contribute to the increased prevalence of obesity (Burke et al., 2010; Johnson et al., 2008; Johnson-Taylor et al., 2008). The growing prevalence of overweight and obesity could change the subjective threshold for what most people consider a “normal” weight level, thereby resulting in under-detection of overweight and obesity (Robinson, 2017). This explanation highlights the fact that social context affects weight perceptions (Hammond, 2010; Leahey et al., 2011b; Mueller et al., 2010; Robinson and Kirkham, 2014) because individuals adjust perceptions of their own weight based on the weight of those around them (Ali et al., 2011; Burke and Heiland, 2007; Maximova et al., 2008; Robinson, 2017)” https://pmc.ncbi.nlm.nih.gov/articles/PMC6304710/

The comically fat guy on some old shows looks reasonably normal today. However being overweight with a high fat person simply isn’t healthy. The healthy person who doesn’t exercise much should be quite thin rather than simply replacing muscle with fat and keeping the same weight.