The core assumption here overlooks a very important aspect of closing. The close vote review. Although the close vote review queue is large, the first thing a reviewer will see is the most recently asked question with a close vote according to their filter.
This is a contributing factor to closure speed and should not be overlooked. Most questions which are closed do not deserve to be open. And those which do deserve it often are either re-opened or discussed on meta.
Moreover, in the review queue when filtering on a type of closure, users are more likely to choose that same closure reason. While there may be some validity to that being "bandwagoning", people tend to find what they are looking for, and it does not have anything to do with showing the current amount of votes on a question.
When the votes are shown in the close vote review queue, they are not always the same as users tend to choose what they feel fits the question most accurately. Is it a perfect process? No. But I do not believe that showing the counts affects the process negatively.
All that being said, when a close vote specifically for duplicate is showing in a comment, other users will generally be more inclined to agree than to fully analyze. I believe this stems from a reluctance to post duplicate answers, although it will still happen.
As a result of that inclination, when someone points out that your question is a duplicate, and you believe it is not, you must be attentive to that and explicitly define how your question is unique.
In the exact case you link, it is true that you show in your question that you are not interested in the "number_format" (which is the answer in the linked duplicate - although this was reopened, the linked duplicate (confused by PHP's bcmul() scale) was what started this post here on meta), you must make sure to specifically say that your question is not a duplicate of the other post for that exact reason if you want to be fully transparent about the issue.
In conclusion, I do not believe that the vote count leads to bandwagoning - whether it is shown in the review or on the post. I do believe that being attentive will allow your question to remain open and that being attentive is a key part of communication.
P.S. - Closing as duplicate can take some inspection at times, even to familiar users. Perhaps voting to close as duplicate could require at least a score of 5 in one of the tags shared by both the parent and eligible child duplicate.