This idea, that tones are not important, is an extremely widespread misconception, and as I see it, relates to three factors:
1) the general poor quality of western Mandarin education, which allows foreigners to get by without properly learning tones because teachers are too nice to say anything about it,
2) The idea that Mandarin and English are massively and irreconcilably different has led to general ignorance about the language, which in turn leads to amateur-level hacks becoming "experts" by merely knowing more than the absolute minimum about the language, and
3) general politeness shown to foreigners in large Chinese tourist destinations.
Once you get beyond novelty party Chinese, you realize that to be properly understood it is absolutely imperative that your tones are correct. Or, barring that, that you make an effort. And even then it requires greater effort from the hearer to run through the often massive number of possibilities to find the correct utterance.
Please, if you are considering learning Mandarin, don't listen to anyone who tells you that tones do not matter. The above post betrays a fundamental misunderstanding about how the language is spoken.