Why does Cloudflare pose as an ISP?

I am testing a proxy provider and doing my DNS checks - All their proxies return Cloudflare as ISP but they should return the operator/network the proxy has been issued to.

If this happens once or twice I could understand, but no matter the country/location the ISP returns as Cloudflare:

Every IP address on the internet is assigned to a certain AS (Autonomous System)

If you look up the ip addresses with an ASN lookup tool like this one https://hackertarget.com/as-ip-lookup/
you should get CLOUDFLARENET as the ASN name.

This simply means the IP addresses are owned by/assigned to Cloudflare and your proxy provider is using their network to provide you the proxy service (likely they are routing your requests through Cloudflare's Workers service which is basically like a ephemeral vps server running on cloudflare)

it because your proxy provider set their ip to be proxied by cloudflare

wasnt cloudfare on bhw a few yrs back ?

It could also be because your ISP might be using Cloudflare's service to secure their network and they are assigning you a Cloudflare IP instead of their own.

To figure out the cause, you need to perform a similar DNS check without connecting to a proxy.
After that, there are 2 possible scenarios:

1. If you see the same result, then the issue isn't with your proxy provider but on your end.
   In this case, you'll need to manually configure the option to route DNS through the proxy. This is usually done in the browser settings or plugin (whatever you're using for proxy access). This setting is often called "remote DNS option."
   If you're using a socks5 proxy, you definitely need to adjust this setting yourself. Http proxies usually send DNS through the proxy by default (but there can be exceptions).
2. If the DNS check results differ without the proxy, then the Cloudflare issue is indeed because of your proxy provider. Some proxy providers allow changing settings in this regard, so you should ask them.