About the text boxes for posts....

Why is that if a word reaches the end of the margin used for the text in the post, why does it get cut off? As in, for example, if you type in “Happy” but it just shows “Ha”
“ppy”. It just gets really hard to read sometimes when the words don’t move down if it’s too big to fit in the space left in that line of words. How long has it been like this?

Example 2: Blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah, blah.