When people look at your crotch area while you’re wearing grey sweatpants, it could be due to a combination of factors. Here are a few possibilities:

1. Visibility: Grey sweatpants can sometimes be less opaque than other types of pants, especially if they are made from thinner material. This could draw attention to the contours of your body, including the crotch area, and make it more noticeable to others.
2. Contrast: Grey is a neutral color that can create a contrasting effect against the background or other colors. This contrast might make certain areas, such as the crotch, more visually prominent.
3. Cultural and social factors: In some cultures or social contexts, there may be a tendency for people to pay more attention to certain body parts or areas. The crotch area can sometimes be considered a sensitive or private area, and people might glance in that direction out of curiosity or subconscious social conditioning.