Your tweet says there are 6 replies but you only see 2.
You have been blocked by someone but still want to know what they are saying.
Enter the incognito browser window.
If you can’t see replies chances are you have muted the account that is replying, just copy the link to the tweet and open it in an incognito window. The same goes for any profile that has block you, just open the profile in an incognito window.
Unless an account has protected their tweets there is no privacy whatsoever when using the incognito window. and remember this goes both ways 😉