I'm curious about this stance, which I guess is probably the majority view. Why is no amount of injuries an excuse? Surely there is, rationally, a number of injuries which would be considered a reasonable excuse? And if so, where should we actually draw the line? I think something often happens where fans will be quite rational about what can be expected during a short injury crisis and their tolerance threshold simply moves as a crisis drags on.
I think injuries this season have been so debilitating to ETH's ability to ever put players capable of what he wants in the positions he wants them in, not just in one or two positions but in a handful of positions in the majority of games, that I don't think you can really use this season as a measure of how successfully he might manage us in a season with a more typical number of injuries, with someone else in control of transfer business. I just think fewer people agree with me now because there's a fatigue that develops watching your team play badly and lose over an entire season.
Allegations that his transfers and other decisions left us with fewer good options to weather the injury crisis are entirely fair.
And I completely agree with your second paragraph, clearly the injuries can't be viewed as some unavoidable act of god either, and some part/parts of the blame there should fall on the manager.