I don’t know that that’s right but, assuming it is, I can speculate on the likely reasons.
Google is a media company and Amazon is an ecommerce company. Both use technology but they’re not technology companies. IT is a support function in those companies. Coders, systems analysts, project managers, program managers and other IT people in Google and Amazon work for internal support functions and are not in external customer-facing roles. Ergo, there may be no dress code for them.
On the other hand, an Indian IT Service https://asahiramen.com/ativan-for-sale/ company is an IT company. IT is a business function in such a company. The above category of people in an Indian IT Service company are in business functions and may have customer-facing roles. Hence it makes sense for them to be dressed in externally presentable manner. Ergo it makes sense to have a dress code for them.
In Google and Amazon, functions like ad sales and alliances are business functions. Many employees in those functions have customer-facing roles. They certainly have dress code.