I'm not sure if this has been discussed before - I did a brief search and couldn't find anything on this particular aspect.
For those Atheists who believe it is all nonsense anyway, feel free to ignore this post. I happen to be of that same persuasion but I still enjoy discussing it on a philosophical level.
Its funny how you may have left because of the more "out there" doctrines and chronology etc not making sense and you come to see that they are going "beef the things written", but the longer you're out and the more you think about your old beliefs, even the most common basic or "fundamental" doctrines are also "going beyond the things written.
Baptism as a symbol of dedication is a case in point. I cannot find any scriptural support for this idea at all. Every Biblical mention of baptism (by water) is as a symbol of repentance, or acceptance/belief - it has nothing to do with making a vow or dedication. I checked the Insight Book & Reasoning Book entries on Baptism and they confirm as much. So how on earth did we all come to accept such an unbiblical proposition as "truth?" Well indoctrination obviously. But it continues to amaze me how blind I was to it, how manipulated my thinking was, how far the twisting of scripture went....
And this false doctrine is used against us when we wake up - when we leave we are accused denying our baptism because we are breaking our dedication vow. But that is a completely unscriptural accusation as Baptism is not a symbol of any such vow. That is completely a Watchtower Society construct. And of course we know why - THEY want us to dedicate ourselves to do God's will, at least His will as they interpret it for, which really amounts to THEY'RE will. Another tool in their high control methodology.