Why not? "These things are important to play, but you don't need to know them when you build a character because...?" it's okay to suck your first time playing? What is the possible reasoning behind this, other than that's the way most games have traditionally done it?
So this goes off topic into a bigger philosophy of game design but...
I think that if a character sucks because the player didn't know the difference between 'block' and 'parry,' the game has bigger issues.
For one thing I think in designing a game it should be impossible to make a character that sucks. Maybe some character will be more optimal that others, but I think it the game should be made such that a any choice available to a newly made character should all be valid choices. If it's not literally impossible, there should be guidance in the character creation section about what choices to make.
Looking at D&D for this, the biggest choices character have at first level are ability score, race, class, and background. Race, class, and background are all about character concept, so a new player won't run into traps with those. The trick is assigning ability ability scores, which is why 5e includes a "Quick Build" section for each class to tell new players what the highest ability should be for each class.
Also, I know you probably picked your example at random, but I think having two skills where the real-world meaning is basically the same thing, such as 'block' and 'parry,' is bad game design. If they do different things, they should have different names. If they do the same thing, they should be rolled into one skill.
As I mentioned above, I'm playing Exalted, which is pretty ridiculously complicated when it comes to character creation, but at least the the skills are easy to understand by what there name is. If I come up with a concept for a warlord who specializes in mounted archery, I can intuit I need to put points in archery, ride, and war, even if I don't understand the rules of mass combat. (Side note, this is my second campaign of Exalted, and I still don't really know the rules for mass combat).
Finally, in any game where there's a lot of decisions made at character creation, I think there should be a grace period where players can completely re-stat their character if they wish to. This is something I always play with as a house rule, but I think crunchier games should include it rules as written for just the reasons you cite.
I know there's a lot of players who like to read all, or at least most, of the rules before they start play, and that's great for those players. But I also know a lot of players who learn the rules as they go, and I think it's important to character creation just as accessible to those players.