I think we're going to have to agree to disagree on some issues. However, it may be helpful if I explain my position more clearly.
How significant the absence of any known mechanism may be depends on the circumstances. First of all, it depends on how improbable, in terms of known science, such a mechanism needs to be. I chose astrology as my example mainly because there are two levels of improbability involved: first, that the positions of the stars and planets at birth can influence people's futures; second, that (AIUI) the astrological charts have actually drifted way out of line with the actual positions of the planets. That alone should be a strong enough argument to convince any rational person that it's a load of nonsense. There is, of course, another very powerful argument, which is that no properly conducted studies have shown astrology to work. However, the argument against the sheer improbability of any mechanism remains a valid one as a part of the case against it, IMO.
To look at a case from the other end of the probability curve, I have no real problem with not knowing the mechanism for a well-observed phenomenon. Take, say, ball lightning (I think this is the example I'm looking for, but I'm not a physicist). I believe that no-one knows the mechanism by which it is formed, but there is masses of evidence that it does occur. There is no suggestion here that ball lightning somehow breaches the laws of science in the way that astrology does. The mechanism should be a relatively straightforward, physical problem to resolve, it's just that we don't yet have enough information.
As far as the "skeptics or not" issue is concerned, the way I look at it is that there is a gradation between those at one extreme who are skeptical about everything and those at the gullibility end who will unquestioningly believe anything they've read or heard. As with any distribution pattern, very few people occupy either extreme, most are somewhere in between.