That's an interesting question. We now have two cases where IE allows, and may even encourage, sloppy web site design. Is this a good thing? If IE is not enforcing the table, end-table rule, then a page could display in a rather unintuitive way, and the designer may not even catch it. IE also allows images that have incorrect file name extensions. If IE enforced the syntax rules properly, web site designers and HTML posters would catch their errors much earlier. I've used C compilers that don't warn me of NULL pointers. Without a debugging environment that flags this error, a program can appear to work, but fail in strange and hard to track ways. I'd rather be warned.

As for "all the anti-trust hullabaloo," it's not about who makes a better product. It's about stifling competition. Without competition, there's no incentive to make a better product. Sometimes you never know what you don't have because someone actively conspired to prevent it. Like a good cheap electric car years ago. Everyone who tried was litigated into bankruptcy.