I highly doubt that ULX supports any MySQL module by default. People have been generous enough to make addons to support MySQL in ULX, and I guess those use MySQLOO. I'm not sure why you think/where you heard that MySQLOO is vulnerable to being permanently disconnected from the MySQL server by a DDOS.
I would encourage you to be careful of your attitude/tone when asking about people making addons. Might just be me, but I think your comment about people not making a ULX MySQL integration addon using TMySQL4 yet sounded a bit entitled. It's quite a lot of work to integrate MySQL with ULX, and there probably hasn't been one made utilizing TMySQL4 because the people who can and are willing to make a MySQL integration addon wished to use MySQLOO. Just because something might be a better idea doesn't mean it will be done.