There is also no evidence that it was ISIS, unless you take a terrorist group at their word.

I would say there's not enough evidence to come to a definitive conclusion, but there is still plenty of evidence. They were islamist from an area with a lot of Afghan migrants, they were speaking Pashtun, they claimed they had initially been contacted by a priest in a way common place for Isis recruiting, and all this prior to isis claiming responsibility.

there is a lot about the attack that is highly inconsistent with the ISIS MO and that would have been beyond ISIS capabilities to pull off.

How so? Their MO changes based on locality and available resources. In areas where weapons are hard to come by they tend to use knives. In places they can arm their agents with rifles they do so. The only other time there's been a confirmed Isis attack in Russia, it was fairly similar. Gunmen shooting up soft targets.

If you're looking for rock solid evidence that will hold up in court you're probably going to be disappointed. But governments don't need that level of evidence to draw conclusions and to take action against the perpetrators.

I specifically said to ignore the evidence. I just want a rhetoric that actually makes any kind of logical sense.

Everyone who is intellectually honest and not feigning naivety knows who was behind this.

Seems like making that claim is intellectually dishonest..... How do you know? What line of reasoning leads you to make that claim with any degree of certainty? What possible motive would they have?

I'm not making any claims, or even refutting the fact that it very well may have been the west. However, I have not heard anyone make any rhetorical claims or claims backed with enough supporting evidence to make any definitive conclusions.

If you do have a rhetorical based motive that could logically explain why they would back this attack, I would genuinely like to hear it. So far, it doesn't really make any geopolitical sense to me.