They don’t want the hash on the front of the keyword. <a class="twitter-hashtag-button" href="https://twitter.com/intent/tweet?button_hashtag=MyTownTogether">
# has a predefined meaning in a URL context - https://twitter.com/intent/tweet?button_hashtag=#MyTownTogether reads to a browser as "go to https://twitter.com/intent/tweet, send the query string button_hashtag= , and go to the anchor marker MyTownTogether