I watched a TV show where a group of dancers were performing a number. After that, the host interviewed one of the audience and he was told that the Group A's performance was effortless and gave a low rating to that group. However one of judges questioned the audience why did he gave a low score if the performance was effortless.
Usually, if I hear someone's performance described as having been effortless, I assume it was so well executed that every aspect of it looked as though it flowed naturally -- in other words, it was done without apparent effort.
In the case you describe, effortless seems to have been used with a different sense in mind. Specifically, whoever applied the term when describing the dancers' performance was implying that they had made no effort -- in other words, they had not worked very hard on the standard of their performance.
This usage is distinctly different to the normal sense in which the word is applied.
I think this is a good question because "effortless," in my opinion, is another example of a contronym: it can mean both showing no effort (I.E. seemingly "doggin' it"), as well as needing no effort (I.E., performed with ease). The former connotes a lack of commitment, while the latter implies talent that exceeds that normally required to achieve success.
I think the first definition is widely misinterpreted as one who is actually doggin' it, when in reality it only appears that way (which leads to the second, and I believe more accurate, definition).
It sounds like that audience member was confused with the common usage of 'effortless'. There's a distinct difference between saying that the performance was effortless and saying that the performance appeared effortless.
It is far more common in my experience to hear how the actions of some skilled professional appeared effortless. That is, that they are so good at what they do that, to the layman, it appears as if they make no effort at all and yet achieve amazing feats (such as graceful dancing).
It's much rarer to hear the word 'effortless' used to mean that someone has performed so poorly that they seemed to have made no effort.
Since 'effortless' is almost exclusively used to denote expertise, I'd say the audience members' use of the word was incorrect in this context.
My dictionary gives the following explanations and examples for "effortless": Requiring no physical or mental exertion. _I went up the steps in two effortless bounds. Each skill is practiced to the point that it becomes effortless." Achieved with admirable ease: "Her effortless sense of style".
Anyone using the word to indicate something negative just uses it wrong.
I think one has to distinguish between the meaning of a word (as defined in a dictionary) and the way in which it is used (commonly or in a particular case).
Given that it is perfectly possible to use the word "effortless" in a way that doesn't imply any kind of value judgment on the speaker's part, it is clear that there are no positive or negative implications analytically attached to its meaning.
When you use a word in a particular context, however, its meaning will also depend on the linguistic context and the particular situation in which it is used. In this sense, although the first member of the audience didn't use the word "effortless" correctly, we still understand what he meant, because otherwise we wouldn't even be able to judge whether he used the word correctly or not.