Assalamu Alaikum,
First look at the word-by-word translation of 43:17-18:
http://corpus.quran.com/wordbyword.jsp?chapter=43&verse=17The phrase used is "one who is brought up in ornaments, and
he in dispute is not clear." Basically, the verse is saying that the polytheists thought women were only brought up to look pretty, and the
polytheists were in dispute about it. The verse doesn't say that women can't "express themselves in a dispute." The masculine Arabic pronoun is used, showing that the polytheists are the ones who are in dispute, not female children. The pronoun is used to refer to an adult man, not a little girl.
Most of the translations missed out on this part. A better translation for the verse would be something like this: "What use is an offspring that is brought up to be beautiful? He, in dispute, is not clear."
"He" refers to the polytheistic man. This interpretation has been mentioned on a few other websites and fits the Arabic text better.
Verse 43:17 describes a polytheist who is given "good news" (bushra) of a daughter. So according to the Quran, daughters are good news. But the polytheist is not happy about having a daughter, as described in the verse.
According to 81:8-9, some polytheists buried their daughters alive. 43:16 says, "Has He taken daughters and chosen for you sons?" Put together, these verses show that daughters themselves are good news. However, polytheists hated female children and insulted them. Despite the fact that they thought girls were inferior, they still attributed them to God. So the Quran was stating that the polytheists were degrading God by attributing something they hated to Him.
The Quran also condemns those who say God has a son, so it's clear that having children of any gender is beneath Him. However, both sons and daughters are considered a blessing:
"For Allah only is the kingship of the heavens and the earth; He creates whatever He wills; He may bestow daughters to whomever He wills, and sons to whomever He wills. Or may mix them, the sons and daughters; and may make barren whomever He wills; indeed He is All Knowing, Able.” 42:29-50
“And when one among of them receives the glad tidings of a daughter, his face turns black for the day, and he remains seething. Hiding from the people because of the evil of the tidings; "Will he keep her with disgrace, or bury her beneath the earth?"; pay heed! Very evil is the judgment they impose!” 16: 58-59
Other interpretations:
https://newqurantranslation.wordpress.com/2011/07/17/4318/http://seekershub.org/ans-blog/2011/10/03/raised-in-adornments-and-ineffective-in-disputes-the-meaning-and-background-of-verse-4318-of-the-quran/I hope this makes sense