It isn't undue or unfair criticism to say "I looked at these solutions to my problem, here are the issues with those solutions with respect to my problems".
If I have been using a screwdriver deck screws to attach things to my project, and some guy says "hey why don't you just use duct tape", and I explain that duct tape is very useful, but in this case its ugly and doesn't hold stuff on right, am I being unfair to duct tape? What about some guy saying "just use a hammer and nails?" and again, I mention that nails are a decent solution, but screws solve a problem introduced by the nails, am I being unfair to the hammers?
In both cases, the answer is "No". When explaining technical choices, there must be some discussion of why solutions are better or worse. When one of the criteria is speed, calling a rejected solution too slow is not unfair, just fact. It doesn't even speak to other applicability of the solution. Heck, in this case he even explicitly states he likes those tools, meaning that pointing to specific case where they aren't good is probably the opposite of "unfair".
If I have been using a screwdriver deck screws to attach things to my project, and some guy says "hey why don't you just use duct tape", and I explain that duct tape is very useful, but in this case its ugly and doesn't hold stuff on right, am I being unfair to duct tape? What about some guy saying "just use a hammer and nails?" and again, I mention that nails are a decent solution, but screws solve a problem introduced by the nails, am I being unfair to the hammers?
In both cases, the answer is "No". When explaining technical choices, there must be some discussion of why solutions are better or worse. When one of the criteria is speed, calling a rejected solution too slow is not unfair, just fact. It doesn't even speak to other applicability of the solution. Heck, in this case he even explicitly states he likes those tools, meaning that pointing to specific case where they aren't good is probably the opposite of "unfair".