just speaking in terms of the syllabus- the aims of the civil rights movement were to establish racial equality for all, and to end segregation. although segregation has definitely ended because of federal laws, the idea of racial equality still hasn't been achieved in modern day USA. discrimination still exists (even if in a small amount) suggesting that racist elements haven't been addressed. I mean you can see this through the Black Lives Matter movement in 2020- had the laws against discrimination been fully accepted by society why would there now be what some have referred to as "the 21st century civil rights movement".
the thing is there are two sides to every argument in modern- the user above shows one side, and i'm giving you another point of view. for your hsc it's best if you stick with one argument and find the strongest evidence to support it, both can get high marks as long as your argument is well thought out and structured. keep in mind the argument also depends on the question asked- for example the question might specifically refer to 1945-1968 in which case it would be best to stay away from commenting on 21st century America.