Or he causes those who hate or despise him (and won’t change their minds), to seize on these “mistakes” and vent their spleen (and waste their air time) on such nonsensical issues, while he and his team spend their time on tax reform and rolling back the administrative state, both of which are happening.
His opponents are allowing their emotions to cloud their judgment. So he keeps throwing idiotic thing at them which they are compulsive about latching onto. Trump is not like most politicians. He is fully aware that 1/2 the country despise him. He doesn’t care, unlike traditional politicians, and takes full advantage of it.
Whether intentional or unintentional (which depends on your view of Trump), the net effect is that he is succeeding in distracting his opposition.