Faithful-to-God people were vegetarians until after the Flood. Then they could eat the meat of animals (Gen 9:3). Vegetarians today, while they may be doing so for purely nutritional reasons, are unwittingly forbidding themselves what God has allowed.
This was Eve's mistake in the garden, adding more prohibitions than God had. This doesn't help, and often hurts our true godliness (Colossians 2:20-23). To say that science/nutrition knows better than God what is best for us is the height of presumption. We have a hard enough time obeying God's actual commands. Adding to them is often a way for us to excuse our disobedience to them, while pointing to our following our own made-up rules to justify ourselves as righteous. Many today think that if they are being healthy (according to their own standards), then God must favor them, regardless in what other wickedness they indulge.
God also institutes capital punishment, here (Gen 9:5-6). Joe Biden's recent action to change the sentences of death row inmates to life in prison, along with all conviction that capital punishment is wrong, is also the height of presumption. We receive a command from God to punish the murderer, but reject it because we know better than God what is right and wrong.
God restates the dominion mandate to be fruitful and multiply to Noah, and it seems He restates it to the animals as well (Gen 9:7). He already said it to Noah in verse 1, so the "And you" in verse 7 is probably directed to the animals. Confirmation of this comes in verses 8-10, when He makes a covenant with Noah AND all the animals.
The rainbow is God's sign of this covenant, to show us that He will remember the promise to preserve nature until the end. Christians should not let LGBT co-opt this sign for themselves, but should cherish every rainbow in the sky as a renewal of God's promise. The LGBT flag is a counterfeit of this. But you don't stop valuing true currency because there are forgers out there. Take back the rainbow as GOD'S sign of promise to preserve, rather than to pervert, nature.