...I'm not sure how that's offensive, if I'm being honest. If you're purposefully speaking a language poorly with malicious intent, who's the target, literally everyone who speaks Spanish? Spanish is the second most-spoken language in the world, it's such a broad and juvenile insult you'd have to be pretty damn sensitive to take offense to that. Like, if I said, "people with blue eyes are stupid!" who's going to be offended, children?
Anyway... I thought your comment was funny ¯\_(ツ)_/¯
Hablo un poco Español, pero yo quiero aprender más
This is really not surprising to me at all. There are people who major in a language and can hardly speak it all.
I recommend that you reassess the way that you learn. How many hours per day are you reading in Spanish, talking to native speakers, watching movies, etc.? It's very difficult to become fluent in a language by casually taking classes a few times per week.
To become fluent in a language, you have to make it part of your life. It can't just be a casual hobby.
Neither a few casual lessons as a child nor a couple months of Duolingo have trained me nearly well enough in Spanish to speak it well. (MAYBE a couple hundred words at most, and I STILL can't conjugate all that well yet.)
Don't get me wrong, I'll probably keep up the lessons, but my being able to speak it with any fluency is probably going to require knowing a native speaker in-person very well.