I'm not sure where you're getting "rape" from this text. Rape is not condoned in scripture.
Deu 22:25 But if a man find a betrothed damsel in the field, and the man force her, and lie with her: then the man only that lay with her shall die: Deu 22:26 But unto the damsel thou shalt do nothing; there is in the damsel no sin worthy of death: for as when a man riseth against his neighbour, and slayeth him, even so is this matter:
You are looking at the Bible through eyes contaminated by modern feministic philosophy. All marriages were arranged by a matchmaker in the near east at that time and even to this day in many communities - yes, even right here in America.
These girls were not facing any worse of a fate than they would have been if their own fathers arranged a match for them. And the women were treated with compassion compared to all the surrounding cultures.
Deu 21:11 And seest among the captives a beautiful woman, and hast a desire unto her, that thou wouldest have her to thy wife;
Deu 21:12 Then thou shalt bring her home to thine house; and she shall shave her head, and pare her nails;
Deu 21:13 And she shall put the raiment of her captivity from off her, and shall remain in thine house, and bewail her father and her mother a full month: and after that thou shalt go in unto her, and be her husband, and she shall be thy wife.
Deu 21:14 And it shall be, if thou have no delight in her, then thou shalt let her go whither she will; but thou shalt not sell her at all for money, thou shalt not make merchandise of her, because thou hast humbled her.
The usual period of mourning is 7 days - it's called sitting "shiva." These girls were given more than 4x that amount of time. Then, the prospective husband could marry her or let her go for free. That's a way better deal than she would have gotten in her father's house. Even to this day in middle eastern countries (and unfortunately even among immigrants to the west, in case you're not familiar with "honor killings") girls who refuse to marry the man their family chooses are more often than not killed.
You presume your cultural ideas are superior, but that is sheer arrogance. The west's promiscuousness and degradation of women as sex objects is hardly anything to emulate. The women above were financially secure and cared for. Western women today are abandoned like yesterday's leftovers and left to fend for themselves. This is not an improvement.