It’s ignored for several reasons: it’s effectively abandoned with a low
adoption rate, mostly intended for persistent cross-site tracking (which
Goatcounter doesn’t do), and I feel there are some fundamental concerns
with the approach. See
Why GoatCounter ignores Do Not Track
for a more in-depth explanation.
You can still implement it yourself by putting this at the start of the
GoatCounter script:
<script>
(function() {
if ('doNotTrack' in navigator && navigator.doNotTrack === '1')
return;
var script = document.createElement('script');
// [.. rest of standard script omitted ..]
})();
</script>