Sonnendec,
Being a frequent operator into Malaga I can assure you that being vectored out of the way to allow a Spanish national ahead happens regularly. On occassion there maybe sound professional reasons for these vectors but not always, the same applies for Madrid and several other airfields.
I don't think that some controllers realise how good an aid TCAS is an a TMA. It does not take long to figure out what is what and suspicious vectors can be quite obvious.
There is no smoke without fire and some unprofessional controllers are giving Spanish ATC a bad name acoss Europe.