While no doubt some people do feel this way. For the ten thousand and first time, there is a significant and important difference between "lying" and something proving not to have been the case. Again the Russians and every major Western Power believed that Iraq still had chemical weapons.
You're making that up. Virtually every Western intelligence service reported no evidence that Iraq had WMDs. Even Hans Blix came back saying he had found no evidence of WMDs. The CIA and the Pentagon have even had multiple leaks and defectors documenting that they were encouraged to falsify information in order to suggest WMDs, and the majority were completely shocked when WMDs were used as justification for the war. A former Colonel even resigned over the issue when one of her intelligence briefings, which stated categorically that there was no evidence of WMDs, was edited and "redacted" to remove critical words and phrases in order to make it sound as if it supported the WMD theory. The chief informant, the one upon which the majority of the information used to justify the belief that Iraq had WMDs even admitted he lied to the CIA. But anyone who knows anything about HUMINT and SIGINT knows no one acts to this extent on single-source information that can't be verified. No way a CIA case officer would've told his bureau chief he had conclusive evidence based on single-source intel. No way the bureau chief forwards that on even if they did. That's just not how intelligence works. The stakes are far too high. CSIS and the CSE reported they didn't believe Iraq had WMDs prior to the invasion, the same goes for JIC in the UK, France's DGSE and BND/MAD in Germany.
But there is a difference between lying and saying something you aren't sure about. You can read a Ph.D. and Princeton professor's views on the subject in his book "On Bullshit." For the record, he says bullshitting is much, much worse because the bullshitter doesn't care. So even if Bush had no idea his intelligence had been falsified (which is unlikely, he was the Head of State for crying out loud and his dad knew exactly how the CIA worked), the fact that he didn't care that he couldn't back it up made it worse. Or he did lie, which given the cost in terms of lives lost, is still pretty damned horrendous.
In summary, no, the Western Powers didn't believe Iraq had WMDs, and whether you lie or bullshit, you're still a pretty big scumbag when millions of lives hang in the balance.