Exactly the same problem here. I used your commands to completely remove QTCreator but since I have downloaded a few versions from their website and not through APT it didn't do anything.
It looks like there is a wrong path somewhere in the OF code. The compiler is looking for all sorts of Poco library files directly in my home folder.
/home/XXX/openFrameworks/libs/poco/lib/linux64/libPocoNetSSL.a(ConsoleCertificateHandler.o):-1: In function Poco::Net::ConsoleCertificateHandler::onInvalidCertificate(void const*, Poco::Net::VerificationErrorArgs&)':
The file mentioned above is present. Then it starts looking for files in my home folder:
/home/XXX/ConsoleCertificateHandler.cpp:-1: error: undefined reference tostd::cout'`
and so on. 37.000+ times.
Also the newest version of QTCreator (4.4 at the moment) does not work at all with OF. I run QTcreator 4.1.0 on Debian Jessie 8 (Linux 3.16) with KDE desktop.