You kind of answered your own question. They are experienced and have presumably built a team for finance, and operations. Presumably you have no such team in place, nor experience in being a landlord.
This assumes these people you are talking about are actually are telling the truth, keep in mind they may not be in one fashion or another. It is very possible that they do not own as many properties that they claim, they may not be as heavily financed as they claim, or they may be on the verge of bankruptcy. People lie about their situation even when there is no direct benefit to do so. It happens all the time on this site, people ask questions with inflated numbers or fabricated situations.
That part should answer your question. However, here is some more:
Here the bank is doing you a favor and you need to pause and reconsider your situation. Sure if things go great, you can turn a modest investment into a large profit percentage wise compared to your investment. However, it also works both ways. Your 10k or so investment could turn into a 100k loss.
I see you are a PHP developer from your profile. Lets say you were offered an opportunity, give me 10k, and if you do the job perfectly you get 35k. If you do it wrong, you then have to pay an additional 90k. Would you do it? Would you do it if the job was in textile engineering, research chemistry, or locomotive repair? That is basically the deal you are singing up for when choosing to be a landlord without experience or cash.
Real estate can be a great investment. However, rental properties should be paid for with cash. It gives you a large margin of error, and many errors will be made.