To many men, a guy trying to explain the profound impact of a chronic illness on his life just sounds like he's stuck in "Mamby Pamby Land" - as made popular by Sarge in the GEICO commercial. To them, being a man means you earn your own way, that you don't take the easy way out, that even if you're hurting you push through it, that you don't make excuses, that you honor your commitments no matter what...
Even if they accept that your illness is real, they still tend to believe that to be a man you have to push through the illness and not let it interfere with you living up to your responsibilities. Any "complaining" is often just dismissed as weakness. And if the illness is "invisible", you're just going to have a hard time convincing them that this not primarily a character issue.
It's not that women don't experience similar treatment, but for a man, living with a chronic illness can devastate his self-esteem and his self-respect. Even though most of my male friends and family members are supportive, I just don't feel that they respect me like they did when I was holding down a job and never even drove through "Mamby Pamby Land"...