This isn't necessarily deliberate. Example: years ago at Google we had proxies for Web traffic. Around lunch time you could hit an issue with HN where the traf

This isn't necessarily deliberate. Example: years ago at Google we had proxies for Web traffic. Around lunch time you could hit an issue with HN where the traffic was blocked for too many visits from the same IP. There were thousands of engineers and they were concentrated on 1-2 proxy IPs. A lot of systems tackle potential abuse (eg brute forcing passwords, DoS attacks) with a token and bucket algorithm. Example: a given source IP might get 20 tokens. Each visit uses a token and those tokens are regenerated 1 per 2 seconds. So with a Tor exit node you may just be hitting abuse protection and that could happen on the CDN, gateway servers, internal servers and so on.