I can assure you that it wasn't your sense of humor that caused the comment to be deleted. Many of our users like to interject humourous content into their posts and it usually makes them easier to read then your typical dry textbook prose. We aren't like some other sites that require everything to have a citation from a relible source. Instead, it was deleted because it didn't meet the guidelines for when and how comments should be used on the StackExchange sites.
From the help page on comments:
When should I comment?
You should submit a comment if you want to:
- Request clarification from the author;
- Leave constructive criticism that guides the author in improving the post;
- Add relevant but minor or transient information to a post (e.g. a link to a related question, or an alert to the author that the
question has been updated).
When shouldn't I comment?
Comments are not recommended for any of the following:
- Suggesting corrections that don't fundamentally change the meaning of the post; instead, make or suggest an edit;
- Answering a question or providing an alternate solution to an existing answer; instead, post an actual answer (or edit to expand an
- Compliments which do not add new information ("+1, great answer!"); instead, up-vote it and pay it forward;
- Criticisms which do not add anything constructive ("-1, see previous comments you scallywag!"); instead, down-vote (and provide or up-vote
a better answer if appropriate);
- Secondary discussion or debating a controversial point; please use chat instead;
- Discussion of community behavior or site policies; please use meta instead.
Notice how each of the situations described in the "When should I comment?" list are situations that are short-lived. Comments are supposed to be transient and are used to prompt specific action from someone (for example, an edit to their question or answer) at which point they are deleted, preferably by the person who created it.
If you have the attitude that any comment that you post is only there to accomplish this purpose at which point you will remove it on your own, then you have the right attitude and won't be bothered if someone removes it for you. For the people who don't follow up and delete the comments on their own, there is the ability to flag the comment as obsolete to have it removed.
In your specific case, you actually posted the comment on an answer to the question that was asked.
You actually gave a perfectly acceptable answer to the question that was asked in your comment. Had the comment been on the question instead of on the answer, then while still technically not meeting the comment guidelines (see the second bullet on "When shouldn't I comment?" above), at least it would have made more sense. Sometimes comments are used for this purpose when the poster doesn't have time to write up an entire answer. This can be useful in order to give someone else a start or to get the asker something while they are waiting for other answers. In either case, they should still be considered temporary and expect them to be deleted when they are no longer relevant.
If you have lasting information to add to the site and don't want it to be deleted, then by all means add it as an answer or edit the other persons answer so that it is where it should be.
In response to your comment about answers without references being down voted, please understand that there is no policy to down vote answers that don't have them. It is up to individual voters to decide what they feel is a good or a bad answer and to vote accordingly. The fact of the matter is, not all answers can have references. Generally though, answers that do provide references are higher quality and will gather more up votes/fewer down votes.
I myself sometimes write up answers without references. Sometimes it is because I don't have time to look them up, and sometimes it is just something that I learned and there isn't an official reference that I feel would be helpful. If you write them correctly and are clear, I wouldn't expect them to be down voted.