There’s no need to throw personal insults around. I can read perfectly well, thank you.
People don’t “usually” find it obvious: how could they when so many disabilities are hidden disabilities which aren’t immediately obvious?
What’s your basis for the assertion that “it’s usually obvious when someone has autism of learning disabilities”? It’s well documented that a very high percentage of autistic people are generally able to mask in public - the exception being when they have a meltdown because they are completely overwhelmed. Do you have any credible evidence or statistics at all to support this assertion that you’ve made that it’s “obvious”?
Given the number of autistic people who have to fight for years to get a diagnosis or aren’t even diagnosed until they are adults, it’s clearly not going to be “obvious” to a random bystander whether someone has autism. A very large proportion of autistic people who don’t have learning disabilities put immense effort into masking in public in order to avoid being the target of dreadful behaviour from other people, so you have no idea at all what proportion of autistic people are clearly identifiable as such to a random stranger they encounter in public from your own observations because by definition the only ones that you will know are autistic are those who have told you so or are either having a meltdown at the time or are also intellectually disabled as well as autistic so unable to mask, so you have no idea how many people are in each category.
It would only be possible generally for you to identify that a stranger is autistic in cases where there were also intellectual impairments that prevent the person from masking (when academic research shows clearly that being able to mask generally actually makes things even harder for someone than for someone who can’t mask because the person who can mask gets less support and because masking has been shown by academic research to have an additional and hugely detrimental impact on mental health on top of the impact of dealing with being autistic: being able to mask doesn’t make someone’s support needs or the impact of their autism any lower, it just makes it less visible to others and means they are treated even worse).
There are a great many other medical conditions, too, aside from autism and learning disabilities that cause people to need more consideration or time or may mean they might block a pathway for a couple of minutes, many of which you might not be able to identify just from looking at someone: arthritis, ME, heart conditions, MS, severe asthma, etc.
Your comment was completely unevidenced and betrayed quite a lot of ignorance about autism, which is very concerning from somebody claiming to be a support worker. Your assertion that an appropriate solution would be for autistic people to wear badges or lanyards to mark them out and that this would lead to them being treated better is equally concerning. Do you recommend that everyone should walk around wearing clothing listing their medical history? Would you like to do so?