There are two scenarios being referenced here. The OP is speaking about an interaction on social media. Some others are describing face to face interactions in a gym. Unfortunately, social media has changed the way people relate with one another in person, for the worse..... and nearly all interpersonal communication is suffering.
Before the days of social media, if you were an introvert- perhaps you had one maybe two friends. If you were an extrovert-perhaps you had 4-8. When those people in your "circle" provided commentary or feedback to you, on anything, the way you looked, the way you behaved, the actions you took, the successes and failures you had, either they provided constructive criticism or they offered you affirmation or even edification. Usually, you'd get a mix of both and you valued the positive and the negative, as after all, these were your friends (and presumably they wanted the best for you). You also only received this kind of feedback once a day at best, and in many cases, once every few days or within a week.
The human psyche is not made to have hundreds and in some cases thousands of people offering commentary on your daily look and activities by the hour. When you have 500-1000 people tell you "OMG you look amazing" you start to think you are the star of your own TV show. When the same number of people hate on you for how you look or something you achieved or an opinion you stated, you react defensively and in many cases with equal malevolence.
Its different here on PM as most of us are seeking constructive criticism. We want to hear "you need to bring up your outer sweep" or "start hitting those rear delts". Most of us would be disappointed if our brothers in iron all came back with a generic "you look great" because we are not here to be placated nor patronized. Other social media....not so much. What is particularly sad is how thin skinned social media has made everyone, particularly the younger generation raised on it, as they never established a baseline by having to learn face to face interactions with people who like you, dislike you, hate you, bully you, adore you, etc.
Personally, I am an introvert to begin with, and also a grumpy old man, so I don't have social media (other than PM), and I don't talk to anyone in public. I smile slightly and politely, maybe nod and otherwise keep to myself. It is very rare that I interact with a young person but when I do, I have to remember that a 20 year old today is a completely different breed than 20 year olds 38 years ago when I was that age. Not making excuses for them or stating that we have to accept their every behavior. It is just a reminder to myself that there is no amount of logic or lesson I can apply that will help them understand what I am trying to elucidate.
Getting back to the OP...... what is truly a shame is that along with all of the above, the social media generations have missed some basic manners training. All she had to say was "thank you for your input" and gone about her business, whether she valued the critique or hated it. The ultimate shame is that she left the interaction feeling genuinely attacked when Pesty was authentically trying to help her and had the best intentions.
“The single biggest problem in communication is the illusion that it has taken place.”
― George Bernard Shaw