The masechet-taharot tag seems to be referring to seder Taharos, instead of the masechta included in it with the same name. (It seems that way because there is no "masechta" tag for each individual masechta in Taharos — I tried a few different spellings of "Keilim" and came up with nothing. Also, the only question on it so far is about the seder.
I didn't think it would be appropriate as a tag synonym, since Maseches Taharos and Seder Taharos are certainly not the same thing (though tags like denominations and heterodox did get a little confused).