Statenents can have meaning without embodying knowledge. 'That was a delicious pie' has a clear meaning (if not very precise) but it is unlikely to express knowledge. I doubt if one can know that a pie is delicious because this is not a matter of (objective) truth or falsity, though one can and others may also find it delicious.
You appear to hold a version of what used to be called the emotive theory of ethics but is now referred to as 'expressivism' :
In search of a satisfactory account of moral thought and practice, ethical expressivists
encourage us to ask not about the nature of ethical value but rather about the nature of
ethical evaluations. Their answer to the latter question typically claims some
interesting disanalogy between ethical evaluations and descriptions of the world. We
might call this change in question and the subsequent answer by disanalogy the core
expressivist maneuver. For example, Gibbard writes, "The expressivists' strategy is to
change the question. Don't ask directly how to define 'good'...[rather] shift the
question to focus on judgments: ask, say, what judging that [something] is good
consists in" (2003, p. 6). In early crude forms, the core expressivist maneuver
involved the idea that ethical evaluations are expressions of our noncognitive
sentiments rather than our cognitive representations of things in the world. In later
more refined versions, expressivists have argued that ethical evaluations are
expressions of a special kind of belief whose role in our cognitive economy is
importantly practical rather than representational. (J. Adam Carter and Matthew Chrisman, 'Is epistemic expressivism incompatible with inquiry?', Philosophical Studies: An International Journal for Philosophy in the Analytic
Tradition, Vol. 159, No. 3 (July 2012), pp. 323-339 : 324.)
In other words, for an expressivist a moral judgement is not representational; it does not represent or describe how things objectively are the world (unlike, say, 'The USA is larger in area than the United Kingdom' or 'Sodium is a chemical element'). Rather, a moral judgement expresses an attitude towards persons, actions, character-traits, objects, states of affairs, &c. An attitude (to put it crudely) of approval or disapproval, though a wider and subtler range of moral attitudes can be expressed.
The 'practical' aspect of expressivism is that expressive moral judgements are prescriptive. Not only do they express our own attitudes; they aim to elicit the same attitudes in others. When I say, 'That was a dishonest thing to do', I don't merely express my own attitude to dishonesty, I seek to alter the dishonest attitude of the person concerned or if that's not possible (perhaps they're unknown or have made themselves scarce) to induce or reinforce an attitude of disapproval of dishonesty in others generally.
References
Gibbard, A. 1990. Wise Choices, Apt Feelings: A Theory of Normative Judgement. Oxford: Oxford University Press.
Gibbard, A. 2003. Thinking How to Live. Cambridge, MA: Harvard University Press.
Kalderon, M. 2005. Moral Fictionalism. Oxford: Oxford University Press.
