Why do liberals question my patriotism when I ask questions in this forum?

I pledged allegiance to the flag of the United States of America in grade school. I joined the United States Armed Forces in 1977 and served honorably for 30 years. During this time I swore an oath to the constitution many times, agreeing to uphold and defend it against enemies, foreign and domestic. I am a veteran, decorated, and honorably discharged. Unlike many of my accusers, I obtained my citizenship not only through birth, but by earning it with sweat and blood. Could it be that liberals must resort to ad hominem attacks due to an inability to focus on the real issues posed in my arguments?