Why does gitignore skip files from its list?

Question

git

Hello!
Create .gitignore at the root of the repository and insert 2 lines with file names there:

test1.txt
test2.txt

I commit and push to the GitHub server, and I get this error:

remote: error: File test1.txt is 175.46 MB; this exceeds GitHub's file size limit of 100.00 MB
remote: error: File test2.txt is 19453.43 MB; this exceeds GitHub's file size limit of 100.00 MB

Why does .gitignore skip those files?