What mean here the White and Blacklist ????

https://www.steamgifts.com/about/faq

How does a whitelist work?
If you view a user profile, you'll see a button with a heart icon in the left column. If you click that button, the user will be added to your whitelist. If you click the button again, the user will be removed from your whitelist. When creating a giveaway, you have the option to limit your giveaway to users on your whitelist. By doing so, the giveaway will only be visible and accessible to those users, and only they will be able to enter for a chance to win. If you add new users to your whitelist after your giveaway has been created, those users will instantly gain access to the giveaway as well. If you remove a user from your whitelist, they will no longer have access to your whitelist giveaways, but their entries will remain valid for any previous giveaways they might have entered.

How does a blacklist work?
On user profiles, you'll see a button with a circle icon and a slash through it in the left column. Clicking that button will add the user to your blacklist. Clicking that button again will remove the user from your blacklist. When you blacklist a user they will no longer see your giveaways on the homepage, and they will not be able to view or enter your giveaways from that point forward. If the user entered one of your giveaways prior to being blacklisted, their entry remains valid.
It's important to note that blacklists work two-ways. If you blacklist a user, you will also no longer see their giveaways on the homepage, and you will not be able to view or enter their giveaways.

is that normal

yes

https://www.steamgifts.com/discussion/pxlgT/reasons-for-blacklist

Read this for the many reasons why people blacklist people.

anything under 1000 blacklists is considered normal by the Anonymous Blacklist Association. :3

View attached image.