For user card:
#user-card .card-content .metadata h3:first-of-type { display: none; }
For Profile page (pointless though as the Activity tab will still show your recent activity)
.user-main .about .secondary dl dt:nth-of-type(2), .user-main .about .secondary dl dd:nth-of-type(2), .user-main .about .secondary dl dt:nth-of-type(3), .user-main .about .secondary dl dd:nth-of-type(3) { display: none; }