Have you ever tried to pop a tick? The skin is pretty thick and NOT easily broken. The match doesn't risk breaking the skin of the tick at all. It is simply to get the tick to react temporarily so to get the tweezers around the head to pull out. The tick does NOT pop! Here in the south we use this method all the time.
Lyme disease and other such diseases are called "blood borne". That means that there has to be BLOOD TO BLOOD contact for it to spread. If you have a cut on your finger or other places and the blood of the tick got into it, then it might spread. Otherwise, getting the blood of a tick on you won't do anything. The ticks head being attached does allow a small blood to blood contact to be made, thus spreading the disease.
Alcohol is used more of a disinfectant. It does have little effect on the tick I will admit. However, it does provide a more sterile environment in which to remove the tick. Both the tick, skin, and instrument are somewhat sterilized. If you do "slip" with the tweezers and miss the head, the alcohol may discourage the tick from re-attaching. It's not going to like the smell or recognize it as an immediate blood source.
I've remove many ticks. The match method has worked the best if done properly. The match head is NOT hot enough to puncture anything since it has cooled down significantly by the time it hits the tick. If your worried about anything spreading, then wear rubber gloves.