In this case, it's about numbers.
Clown are an impractical exemple, because:
1) Very few people have phobias about clowns
2) Clowns are very rarely shown in the media
3) Being exposed to clowns when you have that phobia don't have a detrimental effect to your health
As previously stated, it doesn't relate well to the topic at hand and it was not my idea to bring clowns to this conversation.
It's just a poor analogy that detracts from the main topic.