What's the right word for "unclearity"?

You may mean uncertainty:

uncertainty |ˌənˈsərtntē| noun ( pl. -ties) the state of being uncertain : times of uncertainty and danger. • (usu. uncertainties) something that is uncertain or that causes one to feel uncertain : financial uncertainties.

You could use obscurity, such that:

Well, this obscurity was in fact the very reason why I decided to call this meeting tonight.

Which is defined and exemplified over on The Free Dictionary as:

The quality or condition of being imperfectly known or difficult to understand: "writings meant to be understood . . . by all, composed without deliberate obscurity or hidden motives" (National Review).

Or, ambiguity, from the same source as above:

Doubtfulness or uncertainty as regards interpretation: "leading a life of alleged moral ambiguity" (Anatole Broyard).

Or, you could use palpable, I guess:

Easily perceived; obvious

So that the sentence becomes:

Well, this lack of palpability was in fact the very reason why I decided to call this meeting tonight.

But this does alter the sentence more than you desire, just an option.

If you mean "the fact that it was not clearly understandable", then the synonyms can be:

• Unclearness (the best one I guess, derived from "unclear");
• Ambiguity (derived from ambiguous);
• Incomprehensibility (from incomprehensible);
• Opaqueness (fig., derived from "opaque").

If Wiktionary is to be believed, then disclarity is a word, albeit an uncommon one.