1. Enneagram is about compulsive defense strategies. While behavior can indicate this, a simple category like "aggressive" is not sufficient to figure out an enneatype. Any type can have an aggressive or assertive side. Even 9s - I have seen an angry 9, it's not pretty.
2. 6 is overtyped and misunderstood. My theory is that the reason people take 6 suggestions as an insult, and spew them to others as an insult, is because people fear or hate what they can't understand. Type 6 is a complicated type. They are often creative, cryptic, and thinking on many levels at once. I've never met anyone more complicated than a 6. 4's are self-expressive but 6's are creative - sometimes more creative than 4s, because they are driven to push boundaries and challenge systems, whereas 4s are more driven to self-express. A 4's creative work is often autobiographical whereas a 6's comes from the mind and a slew of thoughts that no one else can figure out. So the 6 typing becomes an insult in such communities where the masses simply CANNOT GRASP THEIR COMPLEXITY, whereas, offline, when a 6 encounters enneagram and types herself, she feels just as relieved as any person who understands more about themselves via enneagram.
3. A 6 is not more likely to deny their type than anyone else. I understand projection but there are reasons for various types to deny their typing. 1s and 5s are less likely to deny it, though they can also mistype. Most other types will come up with reasons to mistype. For type 2, 3, 4 they believe they are their image, so if that doesn't match their type description they will mistype. For 6s it's projection, 7s don't want to admit what's wrong with them. Real 8s who keep calm and stay in control won't relate to the overly aggressive descriptions. 9s mold with others and don't look inward. And so forth. 1s mistype as 5s a lot and 5s mistype sometimes because they are not as isolated as described; they have lines to 7 and 8 and have friends and can laugh in public and so forth.
4. The word "intense" SHOULD be attributed to 6 instead of 8. 8s have an intense physical presence and directed rage, and their 'presence of mind' / here-and-nowness ?? in general can be intense. But it is 6s who are most intense in the eyes. Their eyes are the eye of a storm of thoughts spinning around. Look in the eyes of Amy Lee, Matt Bellamy. Music written by 6's is CONSTANT STREAM OF INTENSITY because that is a mirror of what their minds look like. The dynamics and cadences might change but the intensity DOES NOT wax and wane, it is ever present. This is why 6's mistype as 8s and 4s - because descriptions never pay homage to their very obvious intensity. 6s know they are intense, mentally intense, too intense. They can see what their own eyes look like in photos and they know of the intensity in their minds. Since descriptions simply focus on their fears and shortcomings, and don't tend to cover intensity except for 8s, 5s and 4s and SX types - 6s may end up mistyping as 5s, 8s or 4s. This honest and likely mistake should not be mistaken for projection.