I too was a Counselor at a sexual health clinic and I will tell you this: very few people use condoms regularly for every sexual act. Very few. How do I know this? Because people tell their peers and family what they want to hear; they told me the truth.
Most of those that say they use condoms 100% of the time are saying what they know is the right thing to do, not what they actually do. Then there are those that are proud they never stick their bare dicks inside anyone, but will go down on another woman or man in a heartbeat with not a thought of a dental dam or Saran Wrap running through their heads. Yeah, it's smart to protect your penis but not your other orifices. There are a plethora of things that can be transmitted via oral sex.
Every weekend, hundreds of thousands of people in any region go out to party, meet someone, then sleep with them. MOST don't use condoms. That is a fact. For those in this thread that said they use condoms all the time (and aren't fibbing), I commend you. Unfortunately, that isn't the norm. STI rates are out of control for a reason.