I'm not denying it happens. Personally, I'd rather have someone be honest about not being the right partner for me than to pretend and break both of our hearts later when the relationship inevitably crashes and burns.
Being supportive and honest is better overall.
Dating is tricky and it's very individualistic. You're not dating women as a group, you're trying to find a partner. And hopefully that partner is empathetic and caring and supportive and ready for a relationship at the same time you are.