The first misconception is about the origin of the Vedas. The following arguments have been placed by the ignorants:-
World must have begun after Genesis as given by Bible. Hence Vedas must be later than that
Man must have been primitive several thousand years ago. Hence Vedas must be later than that (The fact remains that despite so much of publicity everywhere, including text-books of children and students, there is not one single credible, authoritative evidence – be it in archaeology or otherwise – that can establish the fancy early-man theory and that of evolution of humans from apes from algae from dust etc. Similar is the hoax of Aryan Invasion Theory and that Vedas are compilations of songs sung by shepherds.)
Aryans destroyed Harappan Civilisation, after which they invaded India and brought Vedas with them.
The language of different chapters of Vedas is different. Hence those portions must have been written during times when similar language is observed in other texts.
Vedas contain a word which was used as synonym of Gold in recent times. Thus Vedas must have been written after that.
Vedas contain word Ganga, Yamuna, Saraswati. Hence they must have been written when Saraswati river existed. (This is like saying Mahabharat must have been written recently because it contains mention of Arjun Singh and Lal Krishna Advani!)
In summary, all the reasons provided to date Vedas are based on making the conclusion first (that Vedas are of recent origin) and then trying to cook up reasons. Similar to many corporates deciding to fix the profit numbers first and then preparing the accounts accordingly.
The fact however remains that no one ever could date Vedas. All ancient texts claim Vedas to be ever-present since inception.