Why Vietnam War is known as the 'war we lost on television'?

Answer 1

Because it had alot of publicity, unlike most other wars, and tended to favour the Vietcong's perspective. It was also this level of publicity specifically in the Tet Offensive that caused most US citizens to criticise the war in Vietnam.

Answer 2

It was the first 'television war' because it was the first war that was brought into America's living rooms where many people were exposed greatly to the horrors of war. This was the first war that television acted as the major medium of news for most folks at home.

Please note that the Korean War was also on television, but it was not widely used as a source of war updates for families at home.