Not sure if this feature in BulkEmailer was intended to work the way I was trying to implement it or not, but I did come up with a work around that does what I need it to.
What I did was to add a field called UpdateLink to my SQL view that I am using for recipient data, that creates the entire anchor tag as a string with the UserID already embedded in it.
The sql for my new field looks something like this:
'<a href="http://www.mydomain.com/Volunteers/ClinicUpdate.aspx?DSParam1=' + CAST(UserId AS nvarchar(200)) + '">Cancel Clinic Registration</a>'
When the sql view is run, the result for the UpdateLink field for the user with ID of 8 looks like this:
<a href="http://www.mydomain.com/Volunteers/ClinicUpdate.aspx?DSParam1='8">Cancel Clinic Registration</a>'
I have a MyToken token of [Clinic:Info.UpdateLink(useremail=[User:Emai],expid="14")] which is mapped to the new UpdateLink field in my sql view.
So when I use the above MyToken token in the body of my newsletter, the token is replaced correctly with the entire anchor tag. The link appears and functions correctly in the recipients email. You can even place the above token in a cell within a one cell table and format the cell so that it looks like a button if desired.
I hope this helps someone else who might encounter the same issue when using a token in the href of an anchor tag within an email.