Probably because it isn’t loaded down with ads, pop-ups, and an overly flashy user interface. All the pics are even B&W. I just popped onto Grainger and it’s only a bit slower the McMaster-Carr.
This! A lot of websites crawl while your ad-blocker and their ad-server fight it out.
McMaster has been ahead of the curve for years. Almost 20 years ago when I first started building generators for export I could find, buy and have parts delivered from them so quick I quit searching the local suppliers for hard to find supplies. Saved me time and expense.
It’s the best site our there. Particularly like the detailed drawings of fastenings. Wonder how they get them from different suppliers all same format. Must draw them in house.
I absolutely love McMaster. Just a fantastic company. Agreed on the drawings also. Very convenient.
I haven’t used Grainger in decades.
From reading the comments at the linked tweet apparently the web developers did use faster, lower level tools. Don’t know anything about it but PHP is mentioned.