Can straight pride be considered offensive? If so, why?

I had this discussion with someone I knew for eight years, they've left since then because of our different values that's changed over time.

I understand that if you're straight, you can be an Ally. But in our discussion, it was argued thay if you're an LGBT+ Ally you are also an advocate - I'm not an advocate, but not an antagonist either. I honestly don't care if someone is LGBT+ or not. That facet of somebody is just not something that matters to me. This isn't stated in an offensive way, but moreso I care more about people's values and personality than gender or sexual orientation.

I proposed the idea of displaying heterosexual pride, to more openly represent myself as a straight person because of how many LGBT+ proudly display who they are. I wanted to proudly display something about myself as well.

However, she became upset and stated that showing heterosexual pride is offensive, because it's always weaponized against LGBT+. LGBT+, to my understanding, is a movement accentuating individual freedom and representation.

However, as a heterosexual cis male, I honestly feel demonized. Even when I prompted the idea of getting more involved somewhere LGBT+, like a discord server, I got shut down again - because me making such a decision would be invading a safe space.

So, here I am. Reaching out in the hopes of getting much more I formation about the topic from a more reliable source than terrible news articles.

Edit: I've received both great explanations and a few terrible ones. Regardless, I've been able to glean a lot of valuable information regarding the purpose behind Pride, and being able to read over the replies multiple times to understand it a lot better as compared to vocal explanations as put a lot of things into context.

This thread has done a fine job of explaining things further and explaining why LGBTQ+ operates the way it does, and why straight pride isn't really necessary. I've taken that away most of all. Straight pride isn't necessary, not because it's not okay to have pride in being straight, but because LGBTQ+ pride is not only a way to raise the middle finger to those that demonize LGTBQ+, but to also send a message that despite current events, you guys are here and more than willing to fight back against the norm, therefore fighting to be allowed to be the person they want to be as an individual. To that end, thank you all for your answers.