Westcoast...funny, I have a very similar sample shot taken with my 18-250mm at full 250mm:
Not to say anything insulting about Ken Rockwell, but 'bias' was a pretty good word that would apply...along with 'opinionated', and 'not always right'.
Here's an entire gallery of every photo I've loaded online from my 18-250mm lens - wildlife, night long exposure, handheld high ISO, scenic, architecture, closeup...just about everything and anything, and very much covering the entire focal range:
Sharpness is not an issue - even at full zoom wide open it can still produce pretty decent results, and stopped down a bit it tightens up a lot. Here's a 200mm at ISO1600:
Here's the worst-case scenario - 250mm, wide open:
Sony DSLR-A580 / Sony 18-250mm / Minolta 50mm F1.7 / Sigma 30mm F1.4 / Tamron 10-24mm / Tamron 150-600mm / Tamron 90mm F2.8 macro / Minolta 300mm F4 APO
Sony A6000 / 18-55mm F3.5-5.6 / 55-210mm F4-6.3 / 10-18mm F4 / 35mm F1.8 / 16mm F2.8 / via manual adapter, lots of Pentax K mount, Konica K/AR mount, and Leica M mount manual lenses