The meanings of the Quranic verses can not be taken just from the superficial linguistic meanings. Allah (SWT) Has clearly mentioned in Quran that it is the responsibility of the Prophet (SAWA) to explain to the people the real meanings of Quran (Sura 16, Verse 44).
The meaning of Sura Al-Hamd verses which you quoted never suggest not to seek Waseela. Prophets were mentioned in Quran seeking help from people like Prophet Musa (AS) who asked people for food, and Prophet Sulaiman (AS) who asked people to help him in getting the throne of Bilqees.
We believe that no one can help with out the permission of Allah (SWT).
We do Tawassul because we are been ordered by Allah (SWT) to seek Waseela ( Sura 4, Verse 64.